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call for help with RAID1 ???

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February 27, 2006 1:06:11 PM

Hi everybody. I’ve just bought an extra hard drive of 250GB and I already had one of 120GB.
I'd like to put them in RAID 1 to backup My Documents in a easy way
But I’m not familiar with RAID.
Can somebody answer the following questions?

Is it possible to put a hard drive of 250 GB in RAID1 with a hard drive of 120GB and mirror the one of 120GB on the 205GB HD AND use the free space (250>120) to run XP and other software?
Or do I have to make a partition on the biggest hard drive to make this possible?
And then again, is it possible to put a “partitioned” hard drive in RAID1 without causing problems?

More about : call raid1

a b G Storage
March 2, 2006 2:10:43 AM

windows raid could do it (or was it windows server raid), but raid card wise no, better idea - backup your stuff on both hdds, or buy a raid card and another 120 or 250gb hdd and use a new raid1 setup with 2 hdds.
March 2, 2006 2:24:03 AM

hey i got this cool article about putting HD's into raid if you want it??? Very informative, but only if you have XP PRO and you want it done fast.
Related resources
March 2, 2006 2:24:24 AM

xp doesn't allow for redundent arrays by default. server allows for raid 1 and 5, but there is actually a way to get xp to do all of them, search toms for it!

Raid 1 of the 120 will work, easy way (after fixing xp):

you'll have to install windows on the 120

install the 250 and go to disk manager and set a mirror, it will use 120 of the 250

let it sync, create another drive with the left overs

you have to first convert to dynamic drives though.
March 2, 2006 2:26:13 AM

O for you to put two hard drives into a RAID ARRAY they have to be the exact same drive otherwise there would be very bad problems, so that means you should get another 120, dont be stupid and try cus you might F something up.

Here's how you do it. THis is a whole article on it READ IT

How to set up a RAID array, what performance you can expect from it, and oh ya... a quick explanation of what 'RAID' actually means. - Version 1.0.0

It's an unfortunate fact that hard disk drives are rather slow at storing and retrieving data. Sure they are faster than CDs, linear backup tapes and other removable media, but compared to actual computer memory, they lag behind massively. The mechanical nature of hard disk technology will always hold it back when compared to a purely electronic storage devices such as a stick of RAM. The thing is, our reliance on hard drives has if anything increased over the years, while the technology they are based on has changed little.
Modern software requires ever-increasing amounts of disk space and free memory, leading to constant hard drive access both to retrieve data from the program directory and to store data in the 'virtual memory' space that Windows puts aside on the hard drive.
Hard drives are faster in terms of transferring data than they used to be, mainly do to increases in the speed of the interface (the IDE controller) between the drive and the rest of the computer. Over the course of the last few years, the standard has gone from 33MB/s through 100MB/s and 133MB/s, and now reaches 150MB/s with the new Serial ATA drives.


RAID is an acronym for "Redundant Array of Inexpensive Disks". This describes a configuration for multiple hard drives which provide fault tolerance and improved data access times. RAID was traditionally only found in the domain of servers, but inexpensive IDE RAID solutions now mean many desktop computers can benefit from the same data redundancy, and performance increases for applications like video editing. With the right number of identical hard drives, consumers with motherboards that support IDE RAID can choose from RAID 0, RAID 1, and sometimes even RAID 0+1.
The problem remains that the speed that the controller transfers data can't cover up the real limitation of hard drives, the fact that due to their mechanical nature they can only retrieve and send data to the controller at a certain speed. Improvements in controller technology may make you think the drives are retrieving data faster mechanically, but they are not. Not appreciably faster any ways.
So the fact that controller technology is moving forward while the drive technology behind it is essentially static means that sooner or later, a point is going to come where there is no benefit to increasing controller speed, as the drive cannot mechanically read data fast enough to justify it.
Modern IDE drives are available at speeds of 5400 and 7200 RPM, which indicates how fast the hard disk platters inside the drive are spinning. This ultimately dictates how fast the drive can retrieve and store information.
Since the read/write heads of the drive can move back and forth along the surface of the disk platters, the faster the platter rotates, the quicker the head can reach different sections of the disk; somewhat like like a record player (but not exactly).
There are even 10,000 RPM IDE drives available, generally aimed at business applications and using SCSI (Small Computer Systems Interface) controllers, an alternative to IDE allowing for faster transfer rates, but they are considerably more expensive. These faster drives also require considerable care, as they generate a significant amount of heat, and if not properly mounted may end up damaging themselves in the long term because of this.
The fact that hard drives are limited by the speed that they can send data is not a new issue. Big Business computing has been wrestling with the storage space and cost vs. speed question since hard drives have been around, as well as problems with the reliability of the drives.
RAID Terminology Explained
Hard disks are mechanical devices with moving parts, and as such will break down eventually, compromising any data stored on them that is not backed up. One technology that was developed to deal with this pair of issues is RAID (Redundant Array of Inexpensive Disks).
The idea is to use multiple hard disks in the same system to provide both increased performance (by dividing up data so multiple disks can process different parts of it at the same time) and increased reliability by writing the same information to multiple disks at once.
This technology filtered down to the enthusiast level a while ago, and has become a common feature on many motherboards, as well as an integral part of newer operating systems such as Windows 2000 and XP professional.
In this guide, we will explore how the different implementations of RAID technology function, and how you can make your own RAID setup using a hardware RAID controller, or the software RAID function built into Windows XP Professional.
What is RAID?
RAID, or Redundant Array of Inexpensive Disks, is a technology that uses multiple hard drives to increase the speed of data transfer to and from hard disk storage, and also to provide instant data backup and fault tolerance for any information you might store on a hard drive.
The hard drives are joined in an array (a single logical drive, as far as the operating system is concerned) and all disks share the data written to them in some form. There are several different implementations, or 'levels' of RAID, ranging from RAID 0 to RAID 53.
The common factor that all RAID levels share is the use of a hardware or software RAID controller that intercepts data intended for storage on the logical hard drive. "Logical" being the hard drive space that the operating system sees as a drive letter, C: for example.
This data is then either duplicated by the controller for storage on multiple drives in the array at once ('mirroring'), or broken down into smaller chunks which are then divided between the available drives in the RAID array ('striping'). The terminology that is going to be important to understand from here on in is:
RAID array: A group of hard drives linked together as a single logical drive. Must be connected to one or more hardware RAID controllers, or be attached normally to a computer using a RAID capable operating system, such as Windows XP Professional.
Striping: A procedure in which data sent to a RAID array is broken down and portions of it written to each drive in the array. This can dramatically speed up hard drive access when the data is read back, since each drive can transfer part of the data simultaneously.
Mirroring: A procedure in which data sent to a RAID array is duplicated and written onto two or more drives at once.
By breaking down the data and sharing it amongst two or more drives, higher performance can be achieved, especially when reading data back, as each drive can transfer its portion of the required data simultaneously. Of course, striping data on two or more drives actually reduces reliability, since if a single drive in the array fails, all data is lost as each physical hard disk only contains a fragment of the data which is useless without the rest. To combat this problem, a third RAID technology is used called Parity.
Parity and Common types of RAID
In the majority of RAID implementations, a whole drive, or an area of one or more of the drives in the array is dedicated to storing parity information. Essentially, each time a bit of information (a digital 1 or 0) is written to every drive in a striped RAID array, an additional parity bit is generated and stored. The value of this bit is based on whether the total of the bits written to the striped drives is odd or even.
For example, take a three disk RAID array, in which two drives are striped together to hold data, and the third drive is dedicated to storing the parity information. Each time a bit of data is written to each of the data drives, an additional parity bit is written to the parity drive. For argument's sake, let's say that if the value of the two data bits is even (0 and 0 or 1 and 1) then the value of the parity bit would be 0, and if the value of the two bits is odd (0/1, 1/0) then a 1 would be written.
In this way, if one of the data drives fails, a new drive can be added and by comparing the information present on the surviving data drive with the corresponding parity information from the parity drive, the missing information can be written onto the replacement drive a bit at a time.
If any given bit from the parity drive has a value of 1, then we can see (from the values we laid out above) that the total value of the corresponding data bits must be odd. So by looking at the bit value from the surviving drive, we can determine if the value that needs to be written to the replacement drive should be a '1' or a '0.'
RAID technology began as a method to provide additional data security to business servers, and many of the RAID levels are still almost exclusively used in the business domain, due to the cost of the required hardware. Since the lower levels of RAID are easily implemented on modern computers and need only a pair of drives and a RAID-capable drive controller (hardware) or operating system (software), RAID 0 and RAID 1 implementations have become common in the high end desktop/PC enthusiast market.
RAID 0 is used to gain additional performance from conventional drives by pairing them up, while RAID 1 provides a very simple and effective form of backup by duplicating or 'mirroring' all data on a second drive.
Some common Types of RAID
Most Hardware RAID controllers intended for the enthusiast or small business markets support only three levels of RAID; RAID 0, 1 and 0+1. These are the only levels of RAID that do not require the use of parity, as this feature adds greatly to the complexity and expense of the controller.


RAID 0 uses multiple hard drives to stripe data over one large logical drive. While there are physically two drives, the computer logically sees just one. The RAID 0 configuration is typically used when there are data-intensive applications because it offers the fastest data access, though no redundancy.
Generally speaking, software RAID will not support parity, limiting it to the above three levels of RAID. This is the case with Windows XP Pro.
Raid 0: Striped array without fault tolerance
RAID 0 is the most common 'enthusiast' implementation, and the main reason why hardware RAID controllers have found their way onto desktop motherboards from the back corridors of server rooms and IT departments. The attraction is that RAID 0 can essentially combine two hard drives into one using striping, and greatly increase the speed that the drives transfer data.
RAID 0 requires a minimum of two physical drives, but has the advantage of not requiring a parity drive or using space for parity on any of the disks in the array, allowing their full capacity to be used for data.
Of course, this has one obvious disadvantage. There is no fault tolerance. Period.
In fact, technically the reliability of the logical drive created by this form of RAID array is halved for each physical drive present, since if any drive fails, all the data is lost...
This is not as big a deal as it may sound, since modern drives generally last at least 2-5 years of constant use, and the performance gains make RAID 0 an excellent choice as the operating system and software drive for your computer. Crucial data is best backed up elsewhere however, like on a RAID 1 configuration for instance.
RAID 1 and RAID 0+1 Explained
RAID 1: Mirrored Disk Array A mirrored disk array is composed of a set of two physical hard drives, each of which contains a full copy of all data sent to the logical drive that represents the array. This has a couple of advantages; first of all, any data stored on a RAID 1 array is completely and automatically backed up, and in the event of the failure of one drive, the other can be substituted without a hitch. Secondly, data can be read from both drives simultaneously, increasing the speed of data retrieval.


Fault tolerance is the cornerstone of RAID 1. In this configuration, two identical physical drives are used, with one drive mirroring the information on the other. A RAID 1 configuration is ideal for data redundancy, though storage is more costly as only 1/2 the total drive space of both hard drives is available.
Data writes take just as long as usual however. In the event one of the drives in the array fails, a new drive can be added, the array rebuilt, and the RAID controller will duplicate the information onto the new blank drive.
The disadvantage of RAID 1 is that unlike striping, a mirrored array can use only half of its total free space for storage, since one disk is an exact duplicate of the other.
RAID 0+1 Striped array with mirroring
This RAID level combines the best features of RAID 0 and 1. It requires a minimum of four physical drives to implement, so it is not cheap. Essentially, two pairs of striped drives are mirrored together to provide fault tolerance. The mirroring provides the fault tolerance, though if any drive is lost, it must be immediately replaced and the array rebuilt, since it cannot handle the loss of more than one drive.
RAID 0+1 does retain the inherent disadvantage of mirroring, however; effective disk space is halved since two of the four drives are exact duplicates of the other pair. Many other implementations of RAID exist, nearly all sharing one common factor: The expense and complexity of the hardware controllers required to implement them.
Intended for business use, these levels of RAID use the parity system as explained above to provide varying levels of fault tolerance. RAID solutions at this level generally come as an add-in controller card or a dedicated storage rack and are intended to work hand-in-hand with hot-swappable hard drive mountings. With this setup, any failed drives can be swapped out for new ones on the fly, and the missing data quickly restored by using the parity data.
Many setups will perform this operation automatically while still maintaining close to normal operation.
Hardware or software RAID?
What is better, hardware or software RAID? Good question.
It really depends on your means and expectations. Software RAID setups through an operating system are inherently lower in performance than hardware RAID controllers, due to the lack of dedicated hardware. They also are, in the case of Windows XP Pro at least, much easier to set up and much more flexible in terms of disk use than a hardware based system.
A second factor to consider is whether you want your operating system disk to be part of the RAID array you create? A major limitation of the WinXP RAID implementation is that the operating system must be installed before a RAID array can be created. This means that if you would like to stripe your operating system disk for increased loading speed, you are out of luck unless you go with a hardware RAID controller.
So to cut it short, if you want the maximum benefit out of creating a striped drive, or need to create a RAID 1 mirror for backups, invest in a motherboard with an on board RAID controller or a PCI add-on controller card. If you want to experiment with striped drives for speed, go with the software solution provided by Windows 2000 or XP as it is easier and cheaper.
How to set up Software RAID in windows XP Professional
Like most other hard drive and storage options, RAID is managed through Windows XP's disk management window, found by right clicking on 'my computer,' then selecting 'manage' followed by 'disk management.' Windows XP Professional is only capable of creating RAID 0 striped arrays, while the various Windows Server operating systems can also create software RAID 1 mirror arrays.
Creating a striped RAID array in XP:
For the purpose of this section of the guide we installed two blank 17GB hard drives on a test system. To create a striped array you must first have at least two drives with a portion of 'unpartitioned space' free. The largest stripe you can create will be twice the size of the smallest unused space on either of the disks. If you have two disks, one with 4GB of unpartitioned space and one with 3GB, the largest striped array you could create would be 6GB, as the area of space used by the stripe on each disk must be the same.
The first step is to convert both disks from basic to dynamic disks within Windows. A dynamic disk is a disk that contains an additional database of other dynamic disks on the system. Dynamic disks can only be read by Windows 2000, XP Professional and the various Windows Server operating systems, and are required to create software RAID arrays within Windows.
For more detail on this subject, see PCstats' Guide to the little known features of Windows XP.
To convert the disks from basic to dynamic, right click the grey box on the left that contains the disk names (disk 1, disk 2, etc.) and select 'convert to dynamic disk…'
From the next Window you can check both blank drives and click 'ok' to convert them.

Once both disks are listed as dynamic, right click the 'unpartitioned space' of either drive and select 'new volume.' On the next page we'll set these drives to be striped, and configure the software RAID options.
Setting up a hardware RAID array
In the 'select volume type' Window, select 'striped.'

Add all disks you wish to use, then decide on the amount of space on both disks you wish to use for the striped volume you are about to create. If you wish, you use only part of each disk for the stripe, leaving the rest free for other uses.

Choose a drive letter or folder to use, and the method of formatting, and you are done. The striped array will format and be ready for use.
How to set up hardware RAID:
For this section, we used a Highpoint HPT 372 ATA/133 RAID controller built into an Epox EP-8K5A2+ motherboard. The drives we used to test our RAID configuration were a pair of Seagate Barracuda ATA 5 7200RPM 120GB hard disks. We also set up a second hardware RAID configuration on a Promise 20276 ATA/133 RAID controller built into an MSI KT3 Ultra2 motherboard, attached to the same pair of 17GB drives used in the software RAID setup above. These two controllers are typical of hardware RAID solutions found on modern motherboards and add-in PCI cards.
We wanted to include instructions for both Highpoint and Promise controllers, as these two companies dominate the home desktop and enthusiast market for RAID controllers. Most RAID setup functions are standard, so if you do not have the same exact controller, these instructions should still translate well.
The following instructions assume two identical blank hard disks. It also assumes that you have correctly installed the Windows drivers for your RAID controller. We used the most recent BIOS versions for both controllers, and we recommend that you obtain these from the manufacturer's website if you have not done so already.
Configuring Promise RAID
Note that for the purposes of hardware RAID 0 (striping) it is strongly recommended that you use two disks of the exact same model. For mirror (RAID 1) setups, this is not so essential, but the two drives should be of the same capacity.
Attach the drives to the RAID controller, one drive per channel, set as master for the best performance, and boot the computer. Note that while you can attach both drives to a single IDE port on your RAID controller, you will tend to get better performance with a pair of drives if you plug one into each port during startup, the RAID controller drive detection and setup screen will appear.
Press <CTRL-H> or other key combination as instructed to enter RAID setup.
For Promise RAID controllers
From the main menu, press '1' to enter Auto Setup. From here, you can choose either a RAID 0 or 1 configuration, referred to in this case as either 'performance' or 'security.' Note the separate drive configurations in the screen shots.


Choose and accept the desired RAID type. If you select a stripe (RAID 0) array, no further configuration is necessary. Accept the change and reboot.
If you elect to setup a RAID 1 (mirror) configuration, you must then choose whether you wish to simply create a mirror array (if you have two blank disks and want them to be exact copies when adding data in the future), or create the array and then copy the contents of one disk to the other (if you have a data drive and you wish to create a mirror copy of it for redundancy).
If you elect to mirror and copy data, you will be asked to choose a source drive for the data.

BE CAREFUL. Choosing the wrong drive here can be disastrous, so ensure that you know which drive is which. Paying attention to which port you plugged each drive into should help here, as they will be labeled on the motherboard or card. Once you have created the array, reboot.
Configuring Highpoint RAID controllers
From the main menu, choose 'create RAID'. Press ENTER on the first menu item, 'array mode' and choose either RAID 0 or RAID 1.
The second item, 'select disk drives' lets you specify which drives are included in the array, and if you are using a mirror, lets you choose which drive will be the master in the array. Press ENTER to begin, then press ENTER again to select each drive.
If you are creating a mirror, the first drive you choose will be the master drive and the second will be the mirrored drive. Once you have chosen both, you will be asked whether you wish to duplicate the master drive to the mirror drive now, or simply create the mirror without copying data. Assuming you are using two blank drives, choose the latter option.
For the third item 'block size' accept the default value.
Press ENTER on the fourth item 'start creation process' to create your array. Once you are back to the main menu, press ESC to exit. Your system will reboot.
Initializing and installing (both controllers)
Once Windows loads back up, go to the disk management window. You should be prompted to initialize a new disk. You must do this before Windows XP can access your RAID array. Once you have initialized it, you can right click on the new disk in the disk management lower pane to create a new volume on it and format it in the normal way. You can now use your new RAID volume just like any other drive on your system. As far as windows is concerned, the two disks in your array are one.
Using a hardware RAID array as your system drive
Unlike software RAID arrays, it is actually possible to install Windows or other operating systems onto a hardware array. In the case of Windows, this requires that you have the necessary drivers for your RAID controller on a floppy disk. All hardware controllers should come with this disk; it's the only time you will ever see a driver on a floppy disk these days!
Note that you must have already set up your RAID array through the controller before you attempt to install Windows. Right at the start of the automatic install process for Windows 2000 or XP, as soon as the blue screen appears, you will see a prompt at the bottom of the screen asking you to "Press F6 if you need to install a third party SCSI or RAID driver..."Press F6. Nothing will visibly happen, but after the installation files are copied from the CD, you will see an extra screen for the loading of storage device drivers.

Press 'S' to 'specify an additional device.' You will be prompted to "Please insert the disk labeled Manufacturer-supplied hardware support disk into Drive A:"
Do so and hit enter. After reading the disk, the correct driver for your controller should be shown on screen. Select it and press enter, then enter again to confirm the choice. Windows will then continue to install as normal. And I bet you thought it would be difficult didn't you? Next up, tests to show you just what RAID can do in the performance corner.
The advantages of RAID: Tests
We carried out a set of tests on our Athlon XP 2800+ system equipped with the Highpoint controller and the twin 120GB Seagate ATA-5 drives. Using three different hard disk benchmarks, plus some timed file copies we tried to get a picture of just how much of a real-world performance boost a hardware or software RAID 0 array will give as compared to a single drive. We also tested a RAID 1 configuration to see where it fits in terms of speed.
PCMark 2004
Source: FutureMark


Futuremark's brand new benchmarking program, PCMark 2004, includes 4 separate hard drive performance tests. These use Intel's Rankdisk application to record an isolated simulation of various common Windows disk access events. The performance of the drives in these events is then rated based on the amount of data they were able to transfer per second.
PCMark 2004 HDD Benchmarks - Results
Physical Drive Size XP Startup Application Loading File Copying General HDD Usage
A) No RAID, Single HDD 120GB 7.168 6.536 22.778 5.085
B) Hardware RAID 0 240GB 10.281 7.050 32.104 6.588
Software RAID 0 240GB 10.535 6.984 29.426 6.713
Hardware RAID 1 120GB 8.396 5.391 15.353 5.364
Units: MB/s MB/s MB/s MB/s
The results of the tests speak like this, for the "XP Startup" tests RAID of any sort seems to be an advantage. When we consider "Application Loading," there isn't much of advantage for RAID 0, though you can see a performance handicap imposed by RAID 1 begin to appear. The "File Copying" tests definitely show the advantage of having a RAID 0 setup. Lastly, the "General HDD Usage" tests show surprisingly little difference between a software and hardware RAID 0 array, at least on a fast computer.
SiSoft Sandra 2004
Source: Sandra


Sandra is designed to test the theoretical power of a complete system and individual components. The numbers taken though are again, purely theoretical and may not represent real world performance.
Sisoft Sandra 2004 - Benchmark Results
Avg. Access Time Buffered Sequential Random
Tests: Time: Read: Write: Read: Write: Read: Write:
Single HDD -Standard IDE 7 ms 87 50 41 42 8 9
Hardware RAID 0 6 ms 82 52 80 55 9 11
Software RAID 0 6 ms 82 52 81 55 9 11
Hardware RAID 1 3 ms 89 28 42 27 15 9
Units: milliseconds MB/s MB/s MB/s MB/s MB/s MB/s
You can see the advantage in terms of reading and writing speed that RAID 0 gives, as well as the slow writing performance of RAID 1 quite easily in this benchmark. Still no difference in performance between hardware RAID 0 and software RAID 0.
HD Tach and Timed Data Transfer Tests
HD Tach V2.70
Source: TCD Labs Inc.


HD Tach is a physical performance hard drive test for Windows 95/98/ME and Windows NT/2000. In Windows 9X/ME it uses a special kernel mode VXD to get maximum accuracy by bypassing the file system. A similar mechanism is used in Windows NT/2000/XP. HD Tach reads from areas all over the hard drive and reports an average speed. It also logs the read speeds to a text file that you can load into a spreadsheet and graph to visually read the results of the test.
Hard Drive Tach 2.70 - Benchmark Results
Physical Drive Size Access Time Read Bust Speed Read Speed Max Read Speed Min Read Spin Avg CPU Ultilization
No RAID, Single HDD 120GB 13.8ms 83.0 45.6 22.7 37.6 26.8%
Hardware RAID 0 240GB 13.5ms 83.1 71.4 24.9 40.4 23.6%
(Software RAID 0)* - - - - - - -
Hardware RAID 1 120GB 13.8ms 82.9 32.5 13.2 20.4 19.7%
Units: MB/s MB/s MB/s MB/s
*Unfortunately, as it can only 'see' hardware RAID arrays and not Windows created software RAID arrays, we were unable to use HD Tach to benchmark our software stripe. The traditional drive speed-testing benchmark show us that Hardware RAID 0 offers the fastest data read times, while Hardware RAID 1 offers the best CPU utilization.
Timed Data Transfers
Source: n/a

While not the most scientific of methods, this certainly illustrates real world file copying performance. We hauled the 'I386' directory from a Windows Server CD onto our system drive, then proceeded to copy this 488 MB chunk of many, many files to and from each of our drive configurations several times, averaging the scores. Timing the transfers revealed some interesting things.
Time Data Transfers
Physical Drive Size Upstream Transfer Downstream Transfer
No RAID, Single HDD 120GB 43s 39s
Hardware RAID 0 240GB 33s 34s
Software RAID 0 240GB 33s 35s
Hardware RAID 1 120GB 49s 51s
Units: seconds seconds
Again the performance advantage RAID 0 gives us is clear.
RAID Test conclusions:
Both hardware and software RAID 0 should offer a significant increase in overall hard disk performance to any system. The tradeoff between the two is in expense (if your system does not have a hardware RAID controller built in) vs. the slightly increased load on the CPU that software RAID imposes.
We took screen shots of the task manager CPU usage graph while we were running our file copying tests on both RAID 0 configurations:
Hardware stripe: Software stripe:



Not a huge difference, but it's there. Overall though, either implementation will serve you well.
March 2, 2006 2:30:52 AM

that's not even remotely true, I've had 10, 20, and 40's running various combos of raid 0, 1, and 5 for years without trouble. I never waste a hard drive!

Edit: Man, next time link to it :) 
a b G Storage
March 2, 2006 5:17:16 AM

Quote:
O for you to put two hard drives into a RAID ARRAY they have to be the exact same drive otherwise there would be very bad problems, so that means you should get another 120, dont be stupid and try cus you might F something up.

Here's how you do it. THis is a whole article on it READ IT

How to set up a RAID array, what performance you can expect from it, and oh ya... a quick explanation of what 'RAID' actually means. - Version 1.0.0

It's an unfortunate fact that hard disk drives are rather slow at storing and retrieving data. Sure they are faster than CDs, linear backup tapes and other removable media, but compared to actual computer memory, they lag behind massively. The mechanical nature of hard disk technology will always hold it back when compared to a purely electronic storage devices such as a stick of RAM. The thing is, our reliance on hard drives has if anything increased over the years, while the technology they are based on has changed little.
Modern software requires ever-increasing amounts of disk space and free memory, leading to constant hard drive access both to retrieve data from the program directory and to store data in the 'virtual memory' space that Windows puts aside on the hard drive.
Hard drives are faster in terms of transferring data than they used to be, mainly do to increases in the speed of the interface (the IDE controller) between the drive and the rest of the computer. Over the course of the last few years, the standard has gone from 33MB/s through 100MB/s and 133MB/s, and now reaches 150MB/s with the new Serial ATA drives.


RAID is an acronym for "Redundant Array of Inexpensive Disks". This describes a configuration for multiple hard drives which provide fault tolerance and improved data access times. RAID was traditionally only found in the domain of servers, but inexpensive IDE RAID solutions now mean many desktop computers can benefit from the same data redundancy, and performance increases for applications like video editing. With the right number of identical hard drives, consumers with motherboards that support IDE RAID can choose from RAID 0, RAID 1, and sometimes even RAID 0+1.
The problem remains that the speed that the controller transfers data can't cover up the real limitation of hard drives, the fact that due to their mechanical nature they can only retrieve and send data to the controller at a certain speed. Improvements in controller technology may make you think the drives are retrieving data faster mechanically, but they are not. Not appreciably faster any ways.
So the fact that controller technology is moving forward while the drive technology behind it is essentially static means that sooner or later, a point is going to come where there is no benefit to increasing controller speed, as the drive cannot mechanically read data fast enough to justify it.
Modern IDE drives are available at speeds of 5400 and 7200 RPM, which indicates how fast the hard disk platters inside the drive are spinning. This ultimately dictates how fast the drive can retrieve and store information.
Since the read/write heads of the drive can move back and forth along the surface of the disk platters, the faster the platter rotates, the quicker the head can reach different sections of the disk; somewhat like like a record player (but not exactly).
There are even 10,000 RPM IDE drives available, generally aimed at business applications and using SCSI (Small Computer Systems Interface) controllers, an alternative to IDE allowing for faster transfer rates, but they are considerably more expensive. These faster drives also require considerable care, as they generate a significant amount of heat, and if not properly mounted may end up damaging themselves in the long term because of this.
The fact that hard drives are limited by the speed that they can send data is not a new issue. Big Business computing has been wrestling with the storage space and cost vs. speed question since hard drives have been around, as well as problems with the reliability of the drives.
RAID Terminology Explained
Hard disks are mechanical devices with moving parts, and as such will break down eventually, compromising any data stored on them that is not backed up. One technology that was developed to deal with this pair of issues is RAID (Redundant Array of Inexpensive Disks).
The idea is to use multiple hard disks in the same system to provide both increased performance (by dividing up data so multiple disks can process different parts of it at the same time) and increased reliability by writing the same information to multiple disks at once.
This technology filtered down to the enthusiast level a while ago, and has become a common feature on many motherboards, as well as an integral part of newer operating systems such as Windows 2000 and XP professional.
In this guide, we will explore how the different implementations of RAID technology function, and how you can make your own RAID setup using a hardware RAID controller, or the software RAID function built into Windows XP Professional.
What is RAID?
RAID, or Redundant Array of Inexpensive Disks, is a technology that uses multiple hard drives to increase the speed of data transfer to and from hard disk storage, and also to provide instant data backup and fault tolerance for any information you might store on a hard drive.
The hard drives are joined in an array (a single logical drive, as far as the operating system is concerned) and all disks share the data written to them in some form. There are several different implementations, or 'levels' of RAID, ranging from RAID 0 to RAID 53.
The common factor that all RAID levels share is the use of a hardware or software RAID controller that intercepts data intended for storage on the logical hard drive. "Logical" being the hard drive space that the operating system sees as a drive letter, C: for example.
This data is then either duplicated by the controller for storage on multiple drives in the array at once ('mirroring'), or broken down into smaller chunks which are then divided between the available drives in the RAID array ('striping'). The terminology that is going to be important to understand from here on in is:
RAID array: A group of hard drives linked together as a single logical drive. Must be connected to one or more hardware RAID controllers, or be attached normally to a computer using a RAID capable operating system, such as Windows XP Professional.
Striping: A procedure in which data sent to a RAID array is broken down and portions of it written to each drive in the array. This can dramatically speed up hard drive access when the data is read back, since each drive can transfer part of the data simultaneously.
Mirroring: A procedure in which data sent to a RAID array is duplicated and written onto two or more drives at once.
By breaking down the data and sharing it amongst two or more drives, higher performance can be achieved, especially when reading data back, as each drive can transfer its portion of the required data simultaneously. Of course, striping data on two or more drives actually reduces reliability, since if a single drive in the array fails, all data is lost as each physical hard disk only contains a fragment of the data which is useless without the rest. To combat this problem, a third RAID technology is used called Parity.
Parity and Common types of RAID
In the majority of RAID implementations, a whole drive, or an area of one or more of the drives in the array is dedicated to storing parity information. Essentially, each time a bit of information (a digital 1 or 0) is written to every drive in a striped RAID array, an additional parity bit is generated and stored. The value of this bit is based on whether the total of the bits written to the striped drives is odd or even.
For example, take a three disk RAID array, in which two drives are striped together to hold data, and the third drive is dedicated to storing the parity information. Each time a bit of data is written to each of the data drives, an additional parity bit is written to the parity drive. For argument's sake, let's say that if the value of the two data bits is even (0 and 0 or 1 and 1) then the value of the parity bit would be 0, and if the value of the two bits is odd (0/1, 1/0) then a 1 would be written.
In this way, if one of the data drives fails, a new drive can be added and by comparing the information present on the surviving data drive with the corresponding parity information from the parity drive, the missing information can be written onto the replacement drive a bit at a time.
If any given bit from the parity drive has a value of 1, then we can see (from the values we laid out above) that the total value of the corresponding data bits must be odd. So by looking at the bit value from the surviving drive, we can determine if the value that needs to be written to the replacement drive should be a '1' or a '0.'
RAID technology began as a method to provide additional data security to business servers, and many of the RAID levels are still almost exclusively used in the business domain, due to the cost of the required hardware. Since the lower levels of RAID are easily implemented on modern computers and need only a pair of drives and a RAID-capable drive controller (hardware) or operating system (software), RAID 0 and RAID 1 implementations have become common in the high end desktop/PC enthusiast market.
RAID 0 is used to gain additional performance from conventional drives by pairing them up, while RAID 1 provides a very simple and effective form of backup by duplicating or 'mirroring' all data on a second drive.
Some common Types of RAID
Most Hardware RAID controllers intended for the enthusiast or small business markets support only three levels of RAID; RAID 0, 1 and 0+1. These are the only levels of RAID that do not require the use of parity, as this feature adds greatly to the complexity and expense of the controller.


RAID 0 uses multiple hard drives to stripe data over one large logical drive. While there are physically two drives, the computer logically sees just one. The RAID 0 configuration is typically used when there are data-intensive applications because it offers the fastest data access, though no redundancy.
Generally speaking, software RAID will not support parity, limiting it to the above three levels of RAID. This is the case with Windows XP Pro.
Raid 0: Striped array without fault tolerance
RAID 0 is the most common 'enthusiast' implementation, and the main reason why hardware RAID controllers have found their way onto desktop motherboards from the back corridors of server rooms and IT departments. The attraction is that RAID 0 can essentially combine two hard drives into one using striping, and greatly increase the speed that the drives transfer data.
RAID 0 requires a minimum of two physical drives, but has the advantage of not requiring a parity drive or using space for parity on any of the disks in the array, allowing their full capacity to be used for data.
Of course, this has one obvious disadvantage. There is no fault tolerance. Period.
In fact, technically the reliability of the logical drive created by this form of RAID array is halved for each physical drive present, since if any drive fails, all the data is lost...
This is not as big a deal as it may sound, since modern drives generally last at least 2-5 years of constant use, and the performance gains make RAID 0 an excellent choice as the operating system and software drive for your computer. Crucial data is best backed up elsewhere however, like on a RAID 1 configuration for instance.
RAID 1 and RAID 0+1 Explained
RAID 1: Mirrored Disk Array A mirrored disk array is composed of a set of two physical hard drives, each of which contains a full copy of all data sent to the logical drive that represents the array. This has a couple of advantages; first of all, any data stored on a RAID 1 array is completely and automatically backed up, and in the event of the failure of one drive, the other can be substituted without a hitch. Secondly, data can be read from both drives simultaneously, increasing the speed of data retrieval.


Fault tolerance is the cornerstone of RAID 1. In this configuration, two identical physical drives are used, with one drive mirroring the information on the other. A RAID 1 configuration is ideal for data redundancy, though storage is more costly as only 1/2 the total drive space of both hard drives is available.
Data writes take just as long as usual however. In the event one of the drives in the array fails, a new drive can be added, the array rebuilt, and the RAID controller will duplicate the information onto the new blank drive.
The disadvantage of RAID 1 is that unlike striping, a mirrored array can use only half of its total free space for storage, since one disk is an exact duplicate of the other.
RAID 0+1 Striped array with mirroring
This RAID level combines the best features of RAID 0 and 1. It requires a minimum of four physical drives to implement, so it is not cheap. Essentially, two pairs of striped drives are mirrored together to provide fault tolerance. The mirroring provides the fault tolerance, though if any drive is lost, it must be immediately replaced and the array rebuilt, since it cannot handle the loss of more than one drive.
RAID 0+1 does retain the inherent disadvantage of mirroring, however; effective disk space is halved since two of the four drives are exact duplicates of the other pair. Many other implementations of RAID exist, nearly all sharing one common factor: The expense and complexity of the hardware controllers required to implement them.
Intended for business use, these levels of RAID use the parity system as explained above to provide varying levels of fault tolerance. RAID solutions at this level generally come as an add-in controller card or a dedicated storage rack and are intended to work hand-in-hand with hot-swappable hard drive mountings. With this setup, any failed drives can be swapped out for new ones on the fly, and the missing data quickly restored by using the parity data.
Many setups will perform this operation automatically while still maintaining close to normal operation.
Hardware or software RAID?
What is better, hardware or software RAID? Good question.
It really depends on your means and expectations. Software RAID setups through an operating system are inherently lower in performance than hardware RAID controllers, due to the lack of dedicated hardware. They also are, in the case of Windows XP Pro at least, much easier to set up and much more flexible in terms of disk use than a hardware based system.
A second factor to consider is whether you want your operating system disk to be part of the RAID array you create? A major limitation of the WinXP RAID implementation is that the operating system must be installed before a RAID array can be created. This means that if you would like to stripe your operating system disk for increased loading speed, you are out of luck unless you go with a hardware RAID controller.
So to cut it short, if you want the maximum benefit out of creating a striped drive, or need to create a RAID 1 mirror for backups, invest in a motherboard with an on board RAID controller or a PCI add-on controller card. If you want to experiment with striped drives for speed, go with the software solution provided by Windows 2000 or XP as it is easier and cheaper.
How to set up Software RAID in windows XP Professional
Like most other hard drive and storage options, RAID is managed through Windows XP's disk management window, found by right clicking on 'my computer,' then selecting 'manage' followed by 'disk management.' Windows XP Professional is only capable of creating RAID 0 striped arrays, while the various Windows Server operating systems can also create software RAID 1 mirror arrays.
Creating a striped RAID array in XP:
For the purpose of this section of the guide we installed two blank 17GB hard drives on a test system. To create a striped array you must first have at least two drives with a portion of 'unpartitioned space' free. The largest stripe you can create will be twice the size of the smallest unused space on either of the disks. If you have two disks, one with 4GB of unpartitioned space and one with 3GB, the largest striped array you could create would be 6GB, as the area of space used by the stripe on each disk must be the same.
The first step is to convert both disks from basic to dynamic disks within Windows. A dynamic disk is a disk that contains an additional database of other dynamic disks on the system. Dynamic disks can only be read by Windows 2000, XP Professional and the various Windows Server operating systems, and are required to create software RAID arrays within Windows.
For more detail on this subject, see PCstats' Guide to the little known features of Windows XP.
To convert the disks from basic to dynamic, right click the grey box on the left that contains the disk names (disk 1, disk 2, etc.) and select 'convert to dynamic disk…'
From the next Window you can check both blank drives and click 'ok' to convert them.

Once both disks are listed as dynamic, right click the 'unpartitioned space' of either drive and select 'new volume.' On the next page we'll set these drives to be striped, and configure the software RAID options.
Setting up a hardware RAID array
In the 'select volume type' Window, select 'striped.'

Add all disks you wish to use, then decide on the amount of space on both disks you wish to use for the striped volume you are about to create. If you wish, you use only part of each disk for the stripe, leaving the rest free for other uses.

Choose a drive letter or folder to use, and the method of formatting, and you are done. The striped array will format and be ready for use.
How to set up hardware RAID:
For this section, we used a Highpoint HPT 372 ATA/133 RAID controller built into an Epox EP-8K5A2+ motherboard. The drives we used to test our RAID configuration were a pair of Seagate Barracuda ATA 5 7200RPM 120GB hard disks. We also set up a second hardware RAID configuration on a Promise 20276 ATA/133 RAID controller built into an MSI KT3 Ultra2 motherboard, attached to the same pair of 17GB drives used in the software RAID setup above. These two controllers are typical of hardware RAID solutions found on modern motherboards and add-in PCI cards.
We wanted to include instructions for both Highpoint and Promise controllers, as these two companies dominate the home desktop and enthusiast market for RAID controllers. Most RAID setup functions are standard, so if you do not have the same exact controller, these instructions should still translate well.
The following instructions assume two identical blank hard disks. It also assumes that you have correctly installed the Windows drivers for your RAID controller. We used the most recent BIOS versions for both controllers, and we recommend that you obtain these from the manufacturer's website if you have not done so already.
Configuring Promise RAID
Note that for the purposes of hardware RAID 0 (striping) it is strongly recommended that you use two disks of the exact same model. For mirror (RAID 1) setups, this is not so essential, but the two drives should be of the same capacity.
Attach the drives to the RAID controller, one drive per channel, set as master for the best performance, and boot the computer. Note that while you can attach both drives to a single IDE port on your RAID controller, you will tend to get better performance with a pair of drives if you plug one into each port during startup, the RAID controller drive detection and setup screen will appear.
Press <CTRL-H> or other key combination as instructed to enter RAID setup.
For Promise RAID controllers
From the main menu, press '1' to enter Auto Setup. From here, you can choose either a RAID 0 or 1 configuration, referred to in this case as either 'performance' or 'security.' Note the separate drive configurations in the screen shots.


Choose and accept the desired RAID type. If you select a stripe (RAID 0) array, no further configuration is necessary. Accept the change and reboot.
If you elect to setup a RAID 1 (mirror) configuration, you must then choose whether you wish to simply create a mirror array (if you have two blank disks and want them to be exact copies when adding data in the future), or create the array and then copy the contents of one disk to the other (if you have a data drive and you wish to create a mirror copy of it for redundancy).
If you elect to mirror and copy data, you will be asked to choose a source drive for the data.

BE CAREFUL. Choosing the wrong drive here can be disastrous, so ensure that you know which drive is which. Paying attention to which port you plugged each drive into should help here, as they will be labeled on the motherboard or card. Once you have created the array, reboot.
Configuring Highpoint RAID controllers
From the main menu, choose 'create RAID'. Press ENTER on the first menu item, 'array mode' and choose either RAID 0 or RAID 1.
The second item, 'select disk drives' lets you specify which drives are included in the array, and if you are using a mirror, lets you choose which drive will be the master in the array. Press ENTER to begin, then press ENTER again to select each drive.
If you are creating a mirror, the first drive you choose will be the master drive and the second will be the mirrored drive. Once you have chosen both, you will be asked whether you wish to duplicate the master drive to the mirror drive now, or simply create the mirror without copying data. Assuming you are using two blank drives, choose the latter option.
For the third item 'block size' accept the default value.
Press ENTER on the fourth item 'start creation process' to create your array. Once you are back to the main menu, press ESC to exit. Your system will reboot.
Initializing and installing (both controllers)
Once Windows loads back up, go to the disk management window. You should be prompted to initialize a new disk. You must do this before Windows XP can access your RAID array. Once you have initialized it, you can right click on the new disk in the disk management lower pane to create a new volume on it and format it in the normal way. You can now use your new RAID volume just like any other drive on your system. As far as windows is concerned, the two disks in your array are one.
Using a hardware RAID array as your system drive
Unlike software RAID arrays, it is actually possible to install Windows or other operating systems onto a hardware array. In the case of Windows, this requires that you have the necessary drivers for your RAID controller on a floppy disk. All hardware controllers should come with this disk; it's the only time you will ever see a driver on a floppy disk these days!
Note that you must have already set up your RAID array through the controller before you attempt to install Windows. Right at the start of the automatic install process for Windows 2000 or XP, as soon as the blue screen appears, you will see a prompt at the bottom of the screen asking you to "Press F6 if you need to install a third party SCSI or RAID driver..."Press F6. Nothing will visibly happen, but after the installation files are copied from the CD, you will see an extra screen for the loading of storage device drivers.

Press 'S' to 'specify an additional device.' You will be prompted to "Please insert the disk labeled Manufacturer-supplied hardware support disk into Drive A:"
Do so and hit enter. After reading the disk, the correct driver for your controller should be shown on screen. Select it and press enter, then enter again to confirm the choice. Windows will then continue to install as normal. And I bet you thought it would be difficult didn't you? Next up, tests to show you just what RAID can do in the performance corner.
The advantages of RAID: Tests
We carried out a set of tests on our Athlon XP 2800+ system equipped with the Highpoint controller and the twin 120GB Seagate ATA-5 drives. Using three different hard disk benchmarks, plus some timed file copies we tried to get a picture of just how much of a real-world performance boost a hardware or software RAID 0 array will give as compared to a single drive. We also tested a RAID 1 configuration to see where it fits in terms of speed.
PCMark 2004
Source: FutureMark


Futuremark's brand new benchmarking program, PCMark 2004, includes 4 separate hard drive performance tests. These use Intel's Rankdisk application to record an isolated simulation of various common Windows disk access events. The performance of the drives in these events is then rated based on the amount of data they were able to transfer per second.
PCMark 2004 HDD Benchmarks - Results
Physical Drive Size XP Startup Application Loading File Copying General HDD Usage
A) No RAID, Single HDD 120GB 7.168 6.536 22.778 5.085
B) Hardware RAID 0 240GB 10.281 7.050 32.104 6.588
Software RAID 0 240GB 10.535 6.984 29.426 6.713
Hardware RAID 1 120GB 8.396 5.391 15.353 5.364
Units: MB/s MB/s MB/s MB/s
The results of the tests speak like this, for the "XP Startup" tests RAID of any sort seems to be an advantage. When we consider "Application Loading," there isn't much of advantage for RAID 0, though you can see a performance handicap imposed by RAID 1 begin to appear. The "File Copying" tests definitely show the advantage of having a RAID 0 setup. Lastly, the "General HDD Usage" tests show surprisingly little difference between a software and hardware RAID 0 array, at least on a fast computer.
SiSoft Sandra 2004
Source: Sandra


Sandra is designed to test the theoretical power of a complete system and individual components. The numbers taken though are again, purely theoretical and may not represent real world performance.
Sisoft Sandra 2004 - Benchmark Results
Avg. Access Time Buffered Sequential Random
Tests: Time: Read: Write: Read: Write: Read: Write:
Single HDD -Standard IDE 7 ms 87 50 41 42 8 9
Hardware RAID 0 6 ms 82 52 80 55 9 11
Software RAID 0 6 ms 82 52 81 55 9 11
Hardware RAID 1 3 ms 89 28 42 27 15 9
Units: milliseconds MB/s MB/s MB/s MB/s MB/s MB/s
You can see the advantage in terms of reading and writing speed that RAID 0 gives, as well as the slow writing performance of RAID 1 quite easily in this benchmark. Still no difference in performance between hardware RAID 0 and software RAID 0.
HD Tach and Timed Data Transfer Tests
HD Tach V2.70
Source: TCD Labs Inc.


HD Tach is a physical performance hard drive test for Windows 95/98/ME and Windows NT/2000. In Windows 9X/ME it uses a special kernel mode VXD to get maximum accuracy by bypassing the file system. A similar mechanism is used in Windows NT/2000/XP. HD Tach reads from areas all over the hard drive and reports an average speed. It also logs the read speeds to a text file that you can load into a spreadsheet and graph to visually read the results of the test.
Hard Drive Tach 2.70 - Benchmark Results
Physical Drive Size Access Time Read Bust Speed Read Speed Max Read Speed Min Read Spin Avg CPU Ultilization
No RAID, Single HDD 120GB 13.8ms 83.0 45.6 22.7 37.6 26.8%
Hardware RAID 0 240GB 13.5ms 83.1 71.4 24.9 40.4 23.6%
(Software RAID 0)* - - - - - - -
Hardware RAID 1 120GB 13.8ms 82.9 32.5 13.2 20.4 19.7%
Units: MB/s MB/s MB/s MB/s
*Unfortunately, as it can only 'see' hardware RAID arrays and not Windows created software RAID arrays, we were unable to use HD Tach to benchmark our software stripe. The traditional drive speed-testing benchmark show us that Hardware RAID 0 offers the fastest data read times, while Hardware RAID 1 offers the best CPU utilization.
Timed Data Transfers
Source: n/a

While not the most scientific of methods, this certainly illustrates real world file copying performance. We hauled the 'I386' directory from a Windows Server CD onto our system drive, then proceeded to copy this 488 MB chunk of many, many files to and from each of our drive configurations several times, averaging the scores. Timing the transfers revealed some interesting things.
Time Data Transfers
Physical Drive Size Upstream Transfer Downstream Transfer
No RAID, Single HDD 120GB 43s 39s
Hardware RAID 0 240GB 33s 34s
Software RAID 0 240GB 33s 35s
Hardware RAID 1 120GB 49s 51s
Units: seconds seconds
Again the performance advantage RAID 0 gives us is clear.
RAID Test conclusions:
Both hardware and software RAID 0 should offer a significant increase in overall hard disk performance to any system. The tradeoff between the two is in expense (if your system does not have a hardware RAID controller built in) vs. the slightly increased load on the CPU that software RAID imposes.
We took screen shots of the task manager CPU usage graph while we were running our file copying tests on both RAID 0 configurations:
Hardware stripe: Software stripe:



Not a huge difference, but it's there. Overall though, either implementation will serve you well.


HOLY CRAP

LOL
a b G Storage
March 2, 2006 5:04:23 PM

!