[Cialug] Disk Performance and Measurement

[Aaron Porter]

On Fri, Oct 30, 2009 at 2:11 PM, Nathan C. Smith <nathan.smith at ipmvs.com> wrote:
> I then measured the AoE San performance.  (The Drives are RAID 5)
>
> ServerB:~# hdparm -t --direct /dev/etherd/e200.0p1
> /dev/etherd/e200.0p1:
>  Timing O_DIRECT disk reads:  548 MB in  3.01 seconds = 182.26 MB/sec

Over what kind of interconnect?

> ServerC:~# hdparm -t --direct /dev/sdb1
> /dev/sdb1:
>  Timing O_DIRECT disk reads:  1592 MB in  3.01 seconds = 529.53 MB/sec

O_DIRECT will avoid the system cache, but does this test still fall
inside the 3ware's cache memory? Have you tried iozone or similar?