I'd like to make sure that I'm measuring IOPS correctly across Windows and Linux servers. We're busy trying to figure out which SAN would best suit our environment and measuring IOPS across our servers is the kind of thing I just can't get wrong. Little bit of procurement paranoia kicking in.
On the Windows servers I'm using the \PhysicalDisk(_Total)\Disk Reads/sec and \PhysicalDisk(_Total)\Disk Writes/sec performance counters. On the Linux servers I run vmstat and am looking at the bi (read) and bo (write) counters. I'm pretty sure that I've got this right and that both sets of counters equate to IOPS.
If these counters are correct then I have a problem. The SAN we're going for can handle about 1600 IOPS. Our two mail filter servers, which run MailScanner, MailWatch and Sophos, are hitting around 1500 IOPS collectively. Our two MySQL server run at about 1600 IOPS collectively. We're way over the 1600 IOPS theoretical limit.
Hence the question, am I measuring correctly?