MLC SSDs for 30GB databases

[ochadd]

I did some IOmeter testing comparing a 60gb Vertex to some of our servers. The results are fairly unbelievable. I read the entire IOmeter manual and ran the tests dozens of times and the results always came back the same. Since these are production servers I limited the file size to 1gb and 2gb if that could cause the dramatic results.

Vertex 60gb
5076 Transactions per second
19.8 Read MBps
6.5 Write MBps


3x 15k rpm RAID 5
724 Transactions per second
1.9 Read MBps
1.0 Write MBps

2 x 7200rpm RAID 1
163 Transactions per second
0.6 Read MBps
0.4 Write MBps

3x 7200rpm RAID 5
194 Transactiosn per second
0.5 Read MBps
0.3 Write MBps


Test setup:
Used the default test but set the request size up to 4k and limited the file size to 1GB since these are production machines I can't let the drives fill up.
Size = 4k
67% reads
100% random
16 outstanding IOs/queue depth
2 workers
Ran each test for 10 minutes

I think this should pretty well replicate our worst case scenario on our SQL servers. I tried upping the outstanding IOs up to 32 and 64 and it decimates everything I have access to. MLC drives aren't exactly known as enterprise grade but man do they perform. Copied files to the drive until it was completely full, deleted them, then ran the test.

 

[aceO07]

We're thinking of using SSD for our database (partition) too. However, we haven't gotten to the point of purchasing SSD yet. Probably Intel X25-E.

I remember there was an article with detail analyst of SSD database operations. Unfortunately I can't find that article again. It was definitely from the last couple of months.

 

[ochadd]

Originally posted by: aceO07
We're thinking of using SSD for our database (partition) too. However, we haven't gotten to the point of purchasing SSD yet. Probably Intel X25-E.

I remember there was an article with detail analyst of SSD database operations. Unfortunately I can't find that article again. It was definitely from the last couple of months.

Compared to adding additional SAS drives they are starting to seem like a real option.

147gb SAS drives are still $250. $1k for a RAID 10 setup. A 120GB RAID 1 set using G.skill Falcon drives come in at $640 and offer many times the performance. Wish I could be more confident in their reliability/longevity.

 

[heymrdj]

This it? http://www.anandtech.com/showdoc.aspx?i=3532

 

[aceO07]

Originally posted by: heymrdj
This it? http://www.anandtech.com/showdoc.aspx?i=3532

Great. Thanks. I guess I overlooked it. Did numerous AT and google searches for SSD and SQL.

 

[Rebel44]

Gskill Falcons firmware cant be upgraded by user (IIRC) so I would avoid them - if you want to use MLC SSDs I would recommend Intel SSD or OCZ Vertex. And if you have any problem with Gskill SSD dont expect any help from their support...

 

[ochadd]

Duplicating Anand's IOmeter setup for 100% random 66% reads using 8K requests got me 32MBps on the vertex. Completely different hardware setup but:

1 x SAS 17.0
2 x SAS 26.0
Vertex 32.0
4 x SAS 51.0
1 x X25-E 144

Figuring out the SQLIO benchmark and I'll see where it comes in at.

 

[ochadd]

On a side note... The laptop I have the ssd installed on just started a virus scan and my CPU usage on a 2ghz dual core hung at 100% while the scan ran for 45 seconds

That's awesome