Does anyone have any stats showing Equallogic performance. They claim it does as good or better than any other SAN. What I can't figure out is how it has better performance for SQL if(big if) the databases are set up correctly.
Equallogic takes 14 drives and set them up in one RAID group.
For SQL performance you really need the log on a different RAID group than the database and ideally tempdb to be on at least one other RAID group if not more.
I believe some people would see performance gains, because the databases were never set up properly, so the optimization that Equallogic does would be much better than what they had before.
Does anyone have any experience with this?
It boils down to a few factors, but the way I always look at it is this: if i'm increasing the number of spindles my data is on, it's likely good. Here's something you might see in a database application:
Database volume - 4 10k drives, 560 IOPS of performance available, 560 in use most of the time
Logs volume - 3 10k drives, 420 IOPS of performance available, 280 in use most of the time
Indexes volume - 2 10k drives, 280 IOPS of performance available, 140 in use most of the time
In that situation, the total IOPS my disks can do is 1260, and of that I'm using 980 IOPS. If I were to follow EqualLogic's model and create on RAID set with all 9 drives, and carve those volumes out, my database (which is using everything I'm throwing at it) would be able to make use of the IOPS that the other two volumes don't need. The performance characteristics might look like this:
All volumes - 9 10k drives, 1260 IOPS of total performance available
Database volume - 840 IOPS in use most of the time
Logs volume - 280 IOPS in use most of the time
Indexes volume - 140 IOPS in use most of the time
The fact that the disks (and therefore performance) are shared would only be a bad thing if you don't size your installation properly.