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Multiple HDs with RAID 1 - Lower Maintenance vs. Efficiency

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January 20, 2012 11:32:02 PM

Hi,

I'm looking for input/opinions on which direction to go for a planned database workstation (a Dell T3500 running Windows 7 64-bit). The option I've been asked to spec out is for 2 HDDs, configured for RAID 1 (via a hardware controller). The primary HDD will have an OS partition, and perhaps a 2nd partition (for the data). I'm not having much luck finding clear information about including the OS and software in the mirror. Does this seem like a good way to go? I think for the least amount of impact to the end-user, perhaps. But I don't know what they'll be giving up as far as reads/writes go.

The other option I've considered is using an SSD (or another HDD) for the OS, and then using the 2 HDDs in RAID 1 for the data mirror only. If the OS isn't included in the mirror, then can I safely assume performance would be better? Since the problem we are trying to overt is downtime, if the OS is not included in the mirror, then the end user would end up making images whenever the OS/software is updated.

I work for a company that is spread pretty thin as far as tech support goes, and the end-user doesn't have any experience with RAID to begin with. I don't have that much experience with it either, to be honest. My job is to make sure we have a reliable system in the end with minimal downtime. The last PC had a HD failure, and our tech is unable to support us for a couple of weeks. We do have a robust backup solution, so we've been able to make due on a less-capable PC.

I'd appreciate any input/opinions on which solution seems like the better route to go, over the long run.

Thank you!

MonkeyEdit2000

a c 145 G Storage
January 21, 2012 12:05:46 AM

Raid has several levels as you know

0 - Stripe. Very fast, but when one drive fails, its all gone :( 
1 - Mirror - Safe from a single drive failing. Not always faster. some good hardware cards "may" be able to read faster, writes are always the speed of a single drive(if not slightly slower).
Raid 5 - has a combination of fault tolerance and speed, but needs at least 3 drives. A hardware card is best here as a failed drive will make the setup slow with many host based systems.

It would be beyond the scope of and answer to let you know much more and there is LOTS more.

http://en.wikipedia.org/wiki/RAID

Now for you,

If you want Windows and your DATA separate, then a drive(or small SSD) for windows and a raid1 volume for the DATA would seem to be best.

While now a failure of a DATA drive will not result in data loss or down time(most cards support hot swapping in a new drive).

Deletion or an infection will still effect BOTH drives, so a good backup plan is something you SHOULD get ASAP.

If windows fails, again you have down time, so a backup image of windows every time you have a large change is advisable(so down time is minimal, just restore the image and reboot).

Hope this helps.
January 21, 2012 12:46:52 AM

I appreciate your response and tips, nukemaster. Any other folks out there with an opinion?
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January 21, 2012 8:46:22 PM

I too am interested in your response. I work on very large flies i.e. Excel data spreadsheets, Photo Shop and Video. Where is it more efficient for speed of SSD, OS or DATA. Are the high speed HDDs as effective and efficient? What about reliability...thus the reason for RAID 1. Seems like likelihood of HHD failure is greater than SDD???No?

Would build a bk up image on external media hard drive or disc/dvd?

0 - Stripe. Very fast, but when one drive fails, its all gone :( 
1 - Mirror - Safe from a single drive failing. Not always faster. some good hardware cards "may" be able to read faster, writes are always the speed of a single drive(if not slightly slower).
Raid 5 - has a combination of fault tolerance and speed, but needs at least 3 drives. A hardware card is best here as a failed drive will make the setup slow with many host based systems.

It would be beyond the scope of and answer to let you know much more and there is LOTS more.

http://en.wikipedia.org/wiki/RAID

Now for you,

If you want Windows and your DATA separate, then a drive(or small SSD) for windows and a raid1 volume for the DATA would seem to be best.

While now a failure of a DATA drive will not result in data loss or down time(most cards support hot swapping in a new drive).

Deletion or an infection will still effect BOTH drives, so a good backup plan is something you SHOULD get ASAP.

If windows fails, again you have down time, so a backup image of windows every time you have a large change is advisable(so down time is minimal, just restore the image and reboot).

Hope this helps.[/quotemsg]
a c 145 G Storage
January 21, 2012 9:04:16 PM

Juddinvail said:
I too am interested in your response. I work on very large flies i.e. Excel data spreadsheets, Photo Shop and Video. Where is it more efficient for speed of SSD, OS or DATA. Are the high speed HDDs as effective and efficient? What about reliability...thus the reason for RAID 1. Seems like likelihood of HHD failure is greater than SDD???No?

Would build a bk up image on external media hard drive or disc/dvd?


SSD's have a limited number of write cycles. Some will argue that SSD's are less reliable because of this, but it is quite a few and the drives reads are very fast.

I was generally listing HDD's for large data sets because SSD's are very costly at higher capacities.

If speed is your main concern, SSD's are always the way to go.

As for longevity, SSD's have not logged as many hours as some older hard drive systems yet(and some users will have a strong opinion for or against them). Still early to say for me.

For you, Video editing is generally a sequential thing(you read in order and do not jump all over the drive much). In the case having a hard drive for video in and video out(2 drives) will improve speeds(hard drives are not great at jumping back and forth, so 2 drives will be faster for this then one).

A single SSD for in and out may be as fast or even faster as solid state drives do not have the latency resulting from reading + writing to the same drive at the same time(but i have not tested this in person).

If you can afford a large SSD and it has the space you need, they are generally MUCH faster(even then 4 + drives in raid0. This is again because of the random read/writes being so much better[not drive head to move] on a SSD). The only short coming of SSD's is price/capacity. As with any technology, back-ups are your friend.

As far as a backup goes, it is up to you. External hard drives(ESATA or USB3) tend to be faster then DVD burners. I use external hard drives because of the capacity.
January 21, 2012 9:23:34 PM

THANKS.
So do I understand that for the OS mirroring, an external drive media is suggested as to an optical?

The SSDs alone will not provide for the size of data I often save (cumulatively not at a time, perhaps backing up once every two to three months). Therefore I had intended to often backing up data to large capacity HDD (1tb-2tb HDD or greater) and then removing data from SSDs to make room for more.

While redundant I know, and time consuming, are 2 SDDs for data my best choice for speed and reliability even though size and cost cause me to put final data on separate HDD?

You have any suggestions to better accomplish my needs?
a c 145 G Storage
January 21, 2012 9:59:57 PM

Raid1 Mirroring requires 2(preferably identical drives). But is not considered to be a good backup plan. If the data is erased by mistake or infection, it is still gone off both drives. This is why having a backup is good(Optical or External Tape/Hard drive).

When working on a data set that requires lots of access to the drive(even more so if access is random). a SSD pays off.

For instance, if you are doing video editing, you may have some advantage to using the SSD, but in other cases, you will get hit my the limit of your cpu/gpu for the compression it self. I just do NOT recommend working with video input/output on the same hard drive as it will slow things down quite a bit(cuts speeds at least in half).

What you are doing will depend greatly on the read/write patterns. If a drive is used JUST for one thing(Like video) and the files are not fragmented, a hard drive will work very well because the reads are sequential(as long as it is not writing to it self as well).

Now at the other end, A web server will access DATA from all over the place(different pages,data.) making an SSD much faster at taking lots of users to different pages/data sets.

There is almost no right vs wrong answer, it depends on access patterns.

With SSD's getting faster and faster, they are by and far the future(for ALL workloads). When SSD's came out many users said, "Hey I got X number of drives in Raid0 and it is faster" and it was faster at sequential benchmarks, but random was always faster for the SSD.

Exactly what data are you working with?
January 21, 2012 10:31:15 PM

Windows 7 Professional 64-bit
Asus P8Z68-V LX
IntelĀ® Core i7-2600 3.40 GHz 8M
60 GB Corsair Force Series SATA-III for OS
120GB Corsair Force Series SATA-III (2) for RAID

Most of WORK is large Excel and Quickbooks files. However, third party software is heavy on data used for employee scheduling/time management and interfacing with QB for invoicing.

Secondary use is for pics and artwork utilizing Adobe Photoshop CS and to a lesser extent family video work with Premiere Pro and Pinnacle Studio.

Often I have both monitors filled with multiple windows on each and multiple programs open.


a c 145 G Storage
January 21, 2012 11:38:36 PM

You seem to already have it setup as it should.

I mean the 60gig for windows is fine as long as all the programs you need fit on it.

Now the 120's. If in raid 1, they will have single drive failure fault tolerance(so if one SSD dies, no data is lost). The Capacity will be 120gigabytes

In Raid0, they will have no fault tolerance(1 SSD fails, all data is gone), but faster speeds(access times will still be the same as a single SSD). The capacity will be 240 gigabytes.

So based on your use, you can determine what you need(Speed VS Safe).
January 23, 2012 4:14:22 AM

As I was looking at Mobo, I notice the storage offers 6 x SATA 3Gb/s port(s), and 2 x SATA 6Gb/s port(s). If I proceed with three Ssd, one for OS and two in RAID 1, then I won't have one of the three drivesn utilizing the faster sata 6gb port. As such I assume I'd put the OS drive on the SATA II (3gb) port and place the two data RAIDs on the SATA III ports.

Am I understanding this correctly? If so, are there other Mobo/chip set to consider that offer 3 or more SATA III ports?

Am I being too concerned with a nominal speed difference?


January 23, 2012 8:30:51 AM

Get a hardware RAID card for RAID. That will give you those ports you need for your RAID array(s) and leave your motherboard ports for other things. I agree with nukemaster pretty much. I don't think 120gb is enough for a storage drive though. How about two SSD's in RAID 1 for your OS and two HDD's in RAID 1 for your storage? Or even 4 HDD's in RAID 10 for storage. My RAID 10 array gets 300+ MB/s for reading and 250+ MB/s for writing. I don't know if that would be fast enough for video editing.
January 23, 2012 1:12:54 PM

thanks. simple enough. how do research speed though?
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