Legacy HDS Forums


Discussion created by Legacy HDS Forums on May 22, 2012
Latest reply on Jun 17, 2013 by Legacy HDS Forums
Branched from an earlier discussion

Originally posted by: Newbie


I was reading about disk IOPS and as per the info that I have:

RPM     Drive Type     IOPS
7200     SATA          80-90
10000     SATA          110-125
10000     FC/SAS          130-140
15000     FC/SAS          150-180

RAID Type     Penalty
0 --          1
10 --          2
5 --          4
6 --            6

Please let me know if these numbers are correct.
Also, the formula to calculate RAID IOPS = (Total IOPS*Read percentage)+ (Total IOPS*Write Percentage*RAID Penalty).

So if this formula is true and the above Disk IO numbers and RAID penalties are correct, then to support an application requiring 500 IOPS, with 50% read and 50% write, I would need a RAID 5 config of 1250 IOPS. If I use 15K FC/SAS drives I would need a config of 6D+1P.

I am not considering the Cache on the subsystem, but a generic IO calculation from RAID perspective. Please let me know if I am missing some information or I have some incorrect information.