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RAID 0 with SSD drives. What's the pros and cons?

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March 10, 2011 12:40:06 PM

Hi Tom's Hardware Experts,
I recently came across the problem of using SSD drives to make RAID 0.
I heard quite a few problems with the combination. For example: SSD uses TRIM which is not good for RAID 0.
So I researched a little by myself, that I found
1. the most recent intel RAID controller driver does support TRIM commands pass through.
2. Garbage collection has nothing to do with RAID, it will work as it is.
3. Windows 7 support site says it does make sense to RAID SSD.
4. There are lifespan problem to RAID SSDs.
5. IOPS is going to be the bottleneck for SSD Raid, therefore, no point to do RAID as SSDs are fast enough already.

A lot of these does not explain why RAID 0 is not good, but only better, yet people are not suggesting to do so.
Can anyone explain a little deeper?

And I do have two OCZ vertex 2 60G in RAID 0 running Win7 x64 at the moment. (Asus X58 Sabertooth board) Would it be better if I turn RAID off? any recommendation?

Thank you,
DD
March 10, 2011 1:46:22 PM

Quote:
Use a pci-e add in raid controller.
I know it was mentioned something about sandforce and not handling compressed files too well. Maybe someone else can shed light on that issue I will try to find a link for you.
But that's not a problem the performance difference is huge


Thanks Dadiggle,

But I don't think I'm gonna buy a pci-e raid controller.
With my current onboard intel raid controller, should I keep the RAID 0 configuration?

Cheers,
DD
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March 10, 2011 2:44:22 PM

(1) Trim is NOT passed to SSD if it is a member drive for Raid. It is passed if bios set to raid, BUT SSD is NOT a member drive (Requires Intel Driver 9.6 or later).

(2) On GC - Some drives are better than others - some down right poor, some = Good. I do not seem to recall any that worked as well as trime.

(3) As you already pointed out Raid 0 for SSDs (or HDD) does NOT improve the 4 K random read/writes NOR the access time. It does Improve the Seq read/writes. For this reason Raid0 does little to Improve boot time and/or program load times. Where SSD raid 0 does shine is if you work with (a) large databasses, large cad/cam files, large dot VOBs (DVD files - typically 1 gig files), or blu-ray files which can be up to 40 gigs in size. Dought many will stick a VOB file, or a Blu-ray file on the SSD and edit them.

A single SSD, for Operating system and programs, coupled with a raid0 setup on a pair of HDD might be the better way to go.

Hope this helped.
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March 10, 2011 3:40:15 PM

+1 SSD for O/S and Raid-0 SATA HDD for data.
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March 10, 2011 3:55:51 PM

RetiredChief said:
(1) Trim is NOT passed to SSD if it is a member drive for Raid. It is passed if bios set to raid, BUT SSD is NOT a member drive (Requires Intel Driver 9.6 or later).

(2) On GC - Some drives are better than others - some down right poor, some = Good. I do not seem to recall any that worked as well as trime.

(3) As you already pointed out Raid 0 for SSDs (or HDD) does NOT improve the 4 K random read/writes NOR the access time. It does Improve the Seq read/writes. For this reason Raid0 does little to Improve boot time and/or program load times. Where SSD raid 0 does shine is if you work with (a) large databasses, large cad/cam files, large dot VOBs (DVD files - typically 1 gig files), or blu-ray files which can be up to 40 gigs in size. Dought many will stick a VOB file, or a Blu-ray file on the SSD and edit them.

A single SSD, for Operating system and programs, coupled with a raid0 setup on a pair of HDD might be the better way to go.

Hope this helped.

Thank you RetiredChief

But when you say (1) Trim is NOT passed to SSD if it is a member drive for Raid. It is passed if bios set to raid, BUT SSD is NOT a member drive (Requires Intel Driver 9.6 or later).
does this mean even with the intel driver 9.6, Trim still doesn't work in RAID 0?

I'm actually running two 60G SSD on RAID 0 for OS, virtual memory and main programs (like office and game). I'm using two 500G HDD RAID 0 as secondary game drive and primary data store. Got another 1.5T HDD for data backup.

Any point taking the two SSD off the RAID 0 config? (use one for OS and one for programs?)

Thank you,
DD
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March 10, 2011 7:21:12 PM

(1) That is correct, Trim is NOT passed to SSDs when they are part of a raid configuration even with the latest Intel drivers.

(2) Since you alread have them configured as raid0, I'd probably leave them that way - if you see degrgation in performance the yes break the raid0 config an set them up as two seperate drives. In my estimate, 60 gig is on the small size for operating system and programs. On artical on the new Z68 platform which dealt with SSDs indicated the min size is 80 gigs. I know, some use as small as 40 gigs - But @ 40 -> 60 you are really limited in number of programs you can install.

http://www.tomshardware.com/reviews/z68-express-lucidlo...

If you work with large files, you might think about short stroking your 2 500 gig drives. You loose 500 gigs, but gain in performance. You can google "short stroke" to get a feel if you want to try that.
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March 10, 2011 9:29:28 PM

On the 4k random read/write performance, its all dependant on the stripe size. A 4k stripe will see no improvement since data will not be split among the drives. This goes for hdd's also. Reducing the stripe size should see an improvement but alot depends on the raid controller and how well it handles the smaller stripe (smaller stripe = more work the raid controller has to do)

As for IOP's, I doubt they'd ever be an issue for just about any home user. You worry about IOP's when you start serving files to thousand of people.
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March 10, 2011 9:40:03 PM

Best answer selected by shanghai_stin.
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March 10, 2011 9:42:13 PM

Quote:
that is not correct. it does support trim
http://www.bit-tech.net/news/hardware/2010/03/23/intel-...

Two ssd in raid got a good performance. But the Crappy onboard raid controllers are normally the bottleneck

Tried turning RAID 0 off, only getting half of the performance of almost every size both read and write, only except 4K write is about the same.
Windows do feel a little unresponding compare to when RAIDed

Put RAID 0 back on again.

Thank you for all the help!
Regards,
DD
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March 11, 2011 1:13:55 AM

@ Dagiggle
Read your Link - thought, Great.
The article had a link - it takes you to ver 9.6 which does not support trim in Raid0
Tried to check Intel web site, all I could find is this:
http://www.intel.com/support/chipsets/imsm/sb/CS-031491...

Went back to your artical - It was Dated Mar 23, 2010 - article is in ERROR
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