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Raid SSD question

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February 23, 2010 7:48:23 PM

Currently I have an intel 80 gig SSD, im thinking about buying another intel 80 gig SSD and running them in raid 0. Do SSD's need a special controller to run in raid? or can I set up the raid on the motherboard controller? Also, will SSD's in a raid set up rrun faster if I used a separate controller?

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a c 126 G Storage
February 24, 2010 9:28:54 AM

RAID = RAID; it works on everything that can store data. You could RAID0 your floppy drives if you like; and even your DVD-opticals. Not that it would be useful.

With Intel onboard RAID controller; you have the best RAID engine you can get for Windows. Buying an additional PCI/PCI-express controller would be slower; as you would be using rushed/primitive drivers that offer basic RAID functionality only, and not too great performance.

Please note RAIDs may fail, and you should always have a backup of your precious files. No RAID can ever replace a backup; backups are holy. Worship them!
a b G Storage
February 24, 2010 11:01:45 AM

RAID0 isnt backup, its not really even RAID (redudant) but is striped for PERFORMANCE

other true raids lower risks of hardware failure but still are still not protecting against corruption or virus's or even a simple file deletion etc, its more for better up time if anything

as for RAID0 theres very little overhead or work needed to be performed - if you got onboard RAID its plenty for it.

As for seperate controllers - sometimes its worse because your limited to the port your using (especially bad for PCI) - make sure you use your southbridge's controller if available.
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February 24, 2010 1:10:25 PM

Thanks for the replies, what would guys say the percentage is of raid failing?
a c 126 G Storage
February 24, 2010 4:18:34 PM

RAIDs can 'fail' by two ways; physical disk failures (same as when using the same amount of disks without RAID). But using RAID adds another thing that can fail; a layer on your storage-framework that can malfunction. And that can cause data loss too in some cases.

Many people's fakeRAID arrays under Windows get broken, and poor user judgement may result in actions that permanently destroy data that was otherwise still recoverable - the user just temporarily lost access to it.

Please always focus on a backup, with a backup you don't really have to care about 'reliability', except in some special cases (like servers which can't afford to be 'down') and user data that changes too frequently for a backup to be useful (often replication is an option here).
February 24, 2010 5:41:09 PM

Ok thank you very much for the help
February 24, 2010 9:11:21 PM

I watched a video on how to set up raid for SSD's, but im confused. The guy in the video was using 3 OCZ SSD's and I will have 2 intel SSD's. The part were im confused is installing the raid drivers before windows installation and what strip size to use. I have never done a raid set-up before so any help will be greatly appreciated.
a b å Intel
a c 415 G Storage
February 24, 2010 11:44:42 PM

If you're installing Windows 7 then you shouldn't have to worry about any special drivers as the ones for all of the common Intel ICH chipsets are already built into the Win7 install kit.

Note that if your SSDs are in a RAID array then Windows 7 won't recognize them as SSDs and so it won't perform any of the SSD-specific optimizations such as disabling defragmentation and (especially) TRIM support. It may not align the partitions properly either, although I'm not really sure about that one.
February 24, 2010 11:50:02 PM

yea alignment for a raid setup is the part were im confused, not really sure what to do
a c 126 G Storage
February 25, 2010 5:15:14 AM

Aligned partitions is something you will get when partitioning with Vista or Windows 7, so as long as you avoid XP you won't have a misalignment (only with RAID5 this is still a problem).

By the way sminlal, i heard somewhere that Windows (7?) uses mini-benchmarks on access time to determine if a drive is an SSD or HDD, and enable/disable specific SSD optimizations at that time. That means this should work even with RAID arrays.
a b å Intel
a c 415 G Storage
February 25, 2010 6:17:07 AM

sub mesa said:
i heard somewhere that Windows (7?) uses mini-benchmarks on access time to determine if a drive is an SSD or HDD, and enable/disable specific SSD optimizations at that time. That means this should work even with RAID arrays.
Interesting. So I went and poked around and came up with this link: http://blogs.msdn.com/e7/archive/2009/05/05/support-and...

If you search this page for "SwaroopK" you'll see a post from him which says that if the RAID controller reports the rotational speed of it's virtual volume as "0" then Windows 7 will treat it like an SSD. Of course that begs the question of which RAID hardware and software actually does that. And of course TRIM support is another issue.
February 25, 2010 10:03:55 AM

So is there nothing that I have to do other than set it up in the bios?

EDIT:

The part were im the most confused is alignment. Ive done some research and some people say that Win 7 does it automatically and all I have to do is create the partition in the windows setup screen. Then others say how to do it in the disk repair section with the cmd prompt. I will be using win7 ultimate 64bit with 2 intel SSD's
a b å Intel
a c 415 G Storage
February 25, 2010 4:27:37 PM

Assuming that you create paritions when you install Windows 7, it will align them as long as it knows it's dealing with an SSD.
February 25, 2010 6:57:46 PM

Ok well the video that I watched that said how to align the drives said to set the stripe at 128k, he was using 3 30 gig OCZ vertex drives. I will probably just set it up the windows repair way because I have a tutorial about it now, just not sure on what is the best stripe size to use.
February 26, 2010 12:50:29 PM

csflame4,

One word of caution, from experience.
I bought two 60Gb OCZ SSD's and put them in a RAID0 array for my OS and a few programs to realize the speed increase that RAID0 can give you. My girlfriend went and turned on the stove while the washer and dryer were on, and somehow it tripped the breaker that the computer is on. Needless to say, the computer turned off. Upon reboot, the array was corrupted, and would not boot. (Okay, I thought this was possible, just a pain in the butt to format & reinstall) but, the array was not responding in the BIOS, it only looked as if I has a single SSD. After troubleshooting, I found one of my SSD's controller had freaked out and was identifiying itself as "Barefoot" instead of OCZ and the capacity was wrong 128 instead of 60. The drive would not show up in disk management either. The disk is currently on it's way to OCZ for RMA replacement.
So, long story short, if you plan on using SSD's in RAID, make sure you have an UPS!
a c 126 G Storage
February 26, 2010 1:32:38 PM

A UPS will not protect you against driver-crashes, BSODs, power supply problems, etc.

Also, any broken RAID, especially simple levels like RAID0, are fully recoverable. In most cases, booting an Ubuntu cd gives you instant access to the files. So to get access to your data you should only need a few minutes of time.
a b å Intel
a c 415 G Storage
February 26, 2010 4:39:49 PM

sub mesa said:
In most cases, booting an Ubuntu cd gives you instant access to the files. So to get access to your data you should only need a few minutes of time.

That may be true for someone who knows what they're doing and is familiar with the tools, but it's a whole different story for most of us! :ouch: 
February 26, 2010 11:42:50 PM

Thanks for the replies guys. I have backed up everything and im running raid 0 with 128k stripe and im happy with the speeds. I have one more question though. I my games folder set up as a mirror on the CD so when I play games I will still get the SSD speed but the files will be installed on my storage drive so I dont take up space on the SSD, now when I defrag using diskeeper, it know which disks are SSD's and does not defrag those, but on the mirror partitions I have, is it safe to run a normal defrag on those? Im pretty sue it is I just want to be safe before I do anything.
a c 126 G Storage
February 26, 2010 11:48:14 PM

sminlal said:
That may be true for someone who knows what they're doing and is familiar with the tools, but it's a whole different story for most of us! :ouch: 

No no, as the md driver gets loaded, it would automatically sense the (fake)RAID array because md can read several metadata formats, i.e. nvidia, ati/amd, silicon image, promise, jmicron, intel, etc.

So assuming this all works out, the only thing the user has to do to gain access to his data is open a window and click the " .... Filesystem" to mount the filesystem on the RAID. So with one click, he/she would see the data on the RAID.

Its possible md doesn't properly detect the array first time, for example because some disks don' t have their metadata anymore. Then manual intervention is needed. Something doable for anyone with some time to study its manpage and browse some websites - but more complicated yes.

Still, if it works out of the box the first time, that's pretty slick and very easy.
a b å Intel
a c 415 G Storage
February 27, 2010 3:24:11 AM

sub mesa said:
So assuming this all works out, the only thing the user has to do to gain access to his data is open a window and click the " .... Filesystem" to mount the filesystem on the RAID.
That's very interesting, I didn't know it had that capability built in from the get-go. Do you get that from a standard default install, or is there a pre-installed CD or DVD ISO image that you can use?
a c 126 G Storage
February 27, 2010 7:25:46 AM

It should work with the livecd; so nothing to install.

If all metadata is still intact, and the metadata format ("brand") is supported, it should have already created a /dev/md0 device, which is the RAID array; /dev/md0a would be the first partition.

Thus, normally, all you have to do is click the menu Places, select Home Folder. Then mount the /dev/md0 filesystem by simply clicking on the "....GB Filesystem" mountpoint on the left side of the window.

Should work with some hardware RAID too - for example if your hardware RAID controller died but the disks are fine.
a b å Intel
a c 415 G Storage
February 27, 2010 3:56:38 PM

> It should work with the livecd; so nothing to install.

That could be very useful to know, thanks for passing the info along!
February 27, 2010 7:45:15 PM

Many low end raid controllers actually reduce SSD performance because current gen SSDs are crazy fast.

Also, running your SSD through a RAID setup means no TRIM which will cause gradual slowdown and less longevity.
April 24, 2010 6:04:24 PM

snootch said:
csflame4,

One word of caution, from experience.
I bought two 60Gb OCZ SSD's and put them in a RAID0 array for my OS and a few programs to realize the speed increase that RAID0 can give you. My girlfriend went and turned on the stove while the washer and dryer were on, and somehow it tripped the breaker that the computer is on. Needless to say, the computer turned off. Upon reboot, the array was corrupted, and would not boot. (Okay, I thought this was possible, just a pain in the butt to format & reinstall) but, the array was not responding in the BIOS, it only looked as if I has a single SSD. After troubleshooting, I found one of my SSD's controller had freaked out and was identifiying itself as "Barefoot" instead of OCZ and the capacity was wrong 128 instead of 60. The drive would not show up in disk management either. The disk is currently on it's way to OCZ for RMA replacement.
So, long story short, if you plan on using SSD's in RAID, make sure you have an UPS!




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