hard disk read/write - scsi 10k -> raid 10 7200rpm
- Thread starter Izi
- Start date
SQL server...
Currently I have a site which is on a shared server, but its getting very busy and SQL server is going mental at busy times. I have used SQL profiler and optimized all SQL statments I can, and now going to move it to a new server.
So the current set up is has around 50 sites and 25 DBs on one server. This new server will only have 2 sites and 1 db.
Currently I have a site which is on a shared server, but its getting very busy and SQL server is going mental at busy times. I have used SQL profiler and optimized all SQL statments I can, and now going to move it to a new server.
So the current set up is has around 50 sites and 25 DBs on one server. This new server will only have 2 sites and 1 db.
If it were me, I'd put a busy database on high-tier storage that can do lots of random reads / writes fast, which means SAS / SCSI. RAID on cheaper disks is great for archiving and reading / writing large swathes of data, but I'd guess your database will be slower on the new array. It's slightly complex though, because you've doubled the number of spindles, which might cancel out the performance drop.
Yes, you will see better performance - but only slightly. Firstly it all depends on your type of IO. I recommend getting perfmon loaded and checking to see about your different IO Patterns such as reads / writes, etc. Then use SQLIO.exe to generate IO on your current box (out of hours!!) and then on the new box. Try different RAID configurations on the new box.
If we look at the core maximum random IOPS a drive can handle -
Current: 2 x 10k Drives = 130 IOPS x 2 = 260 IOPS
Proposed: 4 x 7.2k drives = 75 IOPS x 4 = 300 IOPS
Only a slight increase.
However it is a bit more complicated - how you see these IOPS depends on if it is read or write IO.
Random Read IOPS:
Current IOPS = 260 (both drives can be read from)
Proposed IOPS = 300 (all four drives can be read from)
Random Write IOPS:
Current IOPS = 130 (each host access written to one drivee)
Proposed IOPS = 150 (each host access written to two drives)
If you are heavy on reads you might want to consider a RAID 5 3+1 group to claw some capacity back but be wary of the write pentaly for the parity. WIth a similar number of disks RAID 5 will perform very close to RAID 10 in a read heavy environment (80% reads) although some people have found RAID 5 to be just as good. The parity calc really can kill the write though and you may see it able to do half the writes of RAID 10. If your writes are more than 20% avoid RAID 5.
There's a lot of factors to take into consideraton with RAID 5 such as your controller, so take the below numbers as 'finger in the air'.
RAID 5
Read IOPS = 300
Write IOPS = 75
If we look at the core maximum random IOPS a drive can handle -
Current: 2 x 10k Drives = 130 IOPS x 2 = 260 IOPS
Proposed: 4 x 7.2k drives = 75 IOPS x 4 = 300 IOPS
Only a slight increase.
However it is a bit more complicated - how you see these IOPS depends on if it is read or write IO.
Random Read IOPS:
Current IOPS = 260 (both drives can be read from)
Proposed IOPS = 300 (all four drives can be read from)
Random Write IOPS:
Current IOPS = 130 (each host access written to one drivee)
Proposed IOPS = 150 (each host access written to two drives)
If you are heavy on reads you might want to consider a RAID 5 3+1 group to claw some capacity back but be wary of the write pentaly for the parity. WIth a similar number of disks RAID 5 will perform very close to RAID 10 in a read heavy environment (80% reads) although some people have found RAID 5 to be just as good. The parity calc really can kill the write though and you may see it able to do half the writes of RAID 10. If your writes are more than 20% avoid RAID 5.
There's a lot of factors to take into consideraton with RAID 5 such as your controller, so take the below numbers as 'finger in the air'.
RAID 5
Read IOPS = 300
Write IOPS = 75
Associate
One option to increase IOPs on the 7200 rpm drives would be to "short stroke" them.
Accelerate Your Hard Drive By Short Stroking : On The Stroke Of Performance: Hard Drive Short Stroking
It does appear to require a big drop in capacity to achieve this increase however!!
Bob
Accelerate Your Hard Drive By Short Stroking : On The Stroke Of Performance: Hard Drive Short Stroking
It does appear to require a big drop in capacity to achieve this increase however!!
Bob