6 cheap SSD's in a server?

[TechBoyJK]

I'm setting up a server and I'm curious about what you guys think about using a bunch of cheaper SSD's.

It's a Dell PE 2950 with SAS/SATA RAID and 6 drive bays. I'm actually getting another similar server as a backup, and plan to just use 3 x 160GB sata drives in raid 5.

I was thinking

4x60GB SSD in RAID 5
2x60GB SSD as hot spares.

I don't need a whole lot of space. It's just a few small vm's so the RAID 5 array above would be plenty of space.

Thoughts? I was thinking I might find a really good deal on a decent SSD and get 8. 6 for the array above and 2 as spares.

 

[Sleepingforest]

It might be more cost effective to get 3 128GB SSDs in RAID5 and have one 128GB SSD as a hot spare. Generally, you get lower Price/GB as the storage size goes up (up to about 512GB SSD drives).

 

[AdamK47]

Sure, why not? I did and I don't even have a server. They weren't exactly cheap, but much better than enterprise/server class SSDs.

 

[rsutoratosu]

The wear indicator might hit faster than a desktop, so warranty is limited. They may not let you rma drives when the indicator is hit.

How are you mounting these ? does it match up in the chassis ? I have a 2950 but I got the 2.5 drive version, dont have to use a 2.5 to 3.5 into the dell caddy

I end up using external perc raid and hang it to a msa50/75 chassis. Those are super cheap now, you can pick one up on ebay for like 75 bucks, 10 or 25 drive chassis

 

[OlafSicky]

If you won't be writing to them like crazy then why not sounds good. I would use 128gb. I did something similar for a small database server and it's still going strong.

 

[mfenn]

What kind of RAID? I can tell you right now that 4 year old PERC is going to completely choke on the parity calculations required to keep a RAID 5 SSD array busy. They were designed for 15K SAS drives (~200 IOPS at most), and just don't have the parity calculating grunt required for an SSD RAID 5. It would work great in RAID 10 though.

 

[mfenn]

Sure, why not? I did and I don't even have a server. They weren't exactly cheap, but much better than enterprise/server class SSDs.

Yeaaaaaah, No. An array of Vertex 4's will completely melt down when you throw any kind of sustained IOPS-intensive server workload at it. We're talking 2-4K IOPS per drive.

 

[rsutoratosu]

they were probably 6i or something, you can always buy a h700/h710 if needed of ebay

 

[rsutoratosu]

Here's an great perc6i vs h700/h800 on hd & ssd, its basically 3g vs 6g sas

http://www.dell.com/downloads/global/products/pvaul/en/6gbps-vs-3gbps-raid.pdf

 

[AdamK47]

Yeaaaaaah, No. An array of Vertex 4's will completely melt down when you throw any kind of sustained IOPS-intensive server workload at it. We're talking 2-4K IOPS per drive.

I was talking price-wise.

 

[TechBoyJK]

I was thinking that between having some hot spares, and the disk activity being spread out across all the drives, the impact of the lower MTF rates of cheaper drives would be postponed and if the server gets busy enough that the life span of the drives as a whole becomes an issue, it's time to look at getting better drives anyway.

 

[TechBoyJK]

What kind of RAID? I can tell you right now that 4 year old PERC is going to completely choke on the parity calculations required to keep a RAID 5 SSD array busy. They were designed for 15K SAS drives (~200 IOPS at most), and just don't have the parity calculating grunt required for an SSD RAID 5. It would work great in RAID 10 though.

So.. 6 ssd's in a RAID 10 would be better? I just see these cheap SSD's for like $60 for 60GB and I'm trying to figure out a way to use a bunch of cheap drives to create something fairly reliable (and more cost effective than a few 15K SAS drives)

 

[dave_the_nerd]

So.. 6 ssd's in a RAID 10 would be better? I just see these cheap SSD's for like $60 for 60GB and I'm trying to figure out a way to use a bunch of cheap drives to create something fairly reliable (and more cost effective than a few 15K SAS drives)

What are you using the server for? (Or did you say already and I just missed that post?)

 

[TechBoyJK]

What are you using the server for? (Or did you say already and I just missed that post?)

Hosting various vm's. It will be a production box for launching a 'beta' of a web app. I'll have a 2nd server with a few drives sitting around as standby.

Both servers will be running ESXi 5, and I basically plan to have all the vm's (or recent copies) setup on the 2nd server so that all I need to do is backup the data and restore that most current data set to the backup server.

So.. having a nice raid 5 array with a few hot spares, plus routine backups and a spare server ready to go, I was thinking would be a good start until we can afford to get something nicer.

I was even thinking about buying 8 SSD's so I had 2 on hand to put into the array if a drive fails (hot spare would take over, but then I'd need to replace the hot spare).

My thoughts are that if this server gets busy enough that the workload is enough to take down the array or make it unstable, then I'll be willing to buy better drives.

 

[mfenn]

So.. 6 ssd's in a RAID 10 would be better? I just see these cheap SSD's for like $60 for 60GB and I'm trying to figure out a way to use a bunch of cheap drives to create something fairly reliable (and more cost effective than a few 15K SAS drives)

Yes, if you need performance on a relatively slow RAID card, you should go RAID 10. If all you need is capacity and don't care too much about performance, then RAID 5 is fine.