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So we were offered a server to be used as our production DB Server. The biggest difference is that it will contain 6 x 80GB SSD in Hardware RAID 10 using an LSI 8708 RAID Card.

Here are the specs:

  • OS: Windows Server 2008 Standard Edition R2
  • CPU: 2 x Intel Xeon L5620 Quad Core CPU
  • Memory: 8 GB DD3 PC3-1333 MHz RAM
  • HDD: 6 x 80 GB SSD in RAID 10 (Intel X-25-M)
  • RAID Card: LSI 8708 w/ Battery Backup for Write Cache.

We do a lot of writing and reading in the DB.

I know SSDs are relatively new and I'm wondering if it is a good idea to use them in a prod DB Server.

Here are some questions:

  1. I know reading times are very fast, how about writing? Are they faster than normal HDs (in general)?
  2. Do we gain anything in performance by using a RAID 10 configuration with SSDs? Shouldn't just use RAID 1?
  3. Don't SSDs performance degrade with time? I know normal HDs do, but should I be concerned about this or is it still better than the mechanical ones.
  4. Should we format the drives or configure Windows in any specific way to gain any more performance?

Thanks...

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Did they tell you the manufacturer/model of the SSD's? also see: blog.serverfault.com –  Zypher Feb 17 '11 at 21:23
    
I edited the question to include the SSD manufacturer/model –  Jonas Stawski Feb 18 '11 at 2:51
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2 Answers

I know reading times are very fast, how about writing? Are they faster than normal HDs (in general)?

Yes. They're very, very fast if your operating system supports TRIM. Server 2008 R2 does. But TRIM does not work on RAID volumes.

Do we gain anything in performance by using a RAID 10 configuration with SSDs? Shouldn't just use RAID 1?

There's a lot of research out there about RAIDing SSDs. There's some great (albeit older) research done by Toms Hardware here, draw your own conclusions. You will lose the TRIM ability when doing this though.

Don't SSDs performance degrade with time? I know normal HDs do, but should I be concerned about this or is it still better than the mechanical ones.

Traditional HD's only slow down because they get old and start failing, but apart from that a 10-year-old disk should be just as fast as the day it was new, assuming it doesn't have any bad sectors.

Regarding SSD's though, we won't really know until the SSD's that were put into production recently start reaching age. Personally I'm un-decided, and thus steering clear of SSD's as we're contractually obligated to ensure our data maintains its integrity for 7 years, and I'm not risking that on an SSD.

Should we format the drives or configure Windows in any specific way to gain any more performance?

Yes. You should align your partitions.

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+1 couldn't have said it better myself. –  mrdenny Feb 18 '11 at 2:17
    
So if I use RAID, I won't have TRIM, would that make the writing slower than mechanical HDs? Is there a huge difference with and without TRIM? –  Jonas Stawski Feb 18 '11 at 2:52
    
@jstawski - I don't know to be honest, as I've never deployed SSDs into RAID. If you've got them anyway, the best thing you can do is to test it. Set them up individually and do an SQLIO test. Then, RAID them and see what happens to your I/O. –  Mark Henderson Feb 18 '11 at 2:54
    
+1 In addition to aligning partitions (which Windows 6.0+ does automatically) make sure you align the block sizes when running RAID with the File System Allocation Units. Also, using Windows Software RAID will preserve the use of TRIM. –  Chris S Feb 18 '11 at 19:14
    
@Chris - I wondered if dynamic disks in soft-raid would keep TRIM, but I wasn't sure so I decided best not to mention it. Glad you could clarify. –  Mark Henderson Feb 18 '11 at 22:39
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Feel free to use them in a DB box, but make sure you have all the right monitoring tools installed to keep an eye on them, make lots of great backups (and test them) and most importantly add some more memory or you'll end up paging to those SSDs a lot and that will kill them. You should also look at the recommended memory layout of your box as 56xx-series Xeons work best with x3 memory units (i.e. 3, 6, 9, 12, 18 etc. modules) not x2 (i.e. 2, 4, 8, 16 etc.)

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Good point re memory configuration. We used that excuse to jump from 64Gb to 72Gb RAM in our latest DB server. –  Mark Henderson Feb 17 '11 at 21:37
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