I was curious how fast our SAN is when heavy IO load hits the system by multiple processes.
I found a quite handy tool that can run benchmarks quite easily: www.iozone.org

I ran the test with a 5 simultaneous clients, each writes 1GiB to a file in 512KiB blocks.


Click to enlage

Command line:

./iozone -R -l 5 -u 5 -r 512 -s 1g /mnt/10_tib/tmp1 /mnt/10_tib/tmp2 /mnt/10_tib/tmp3 /mnt/10_tib/tmp4 /mnt/10_tib/tmp5

As I had no dedicated testing FCSAN, the tests were performed on a cluster that had more than a dozen VMs running. So the results don't reflect synthetic results but reallife performance. The RAID6 System usually performs backups, but is completely idle during work-time. The SATA System was a fresh installed mainstream rootserver without RAID.

You can see that the FCSAN outperforms a single SATA drive by about 4-10 times. So there is absolutely no way to compare these systems.

A bit more interesting is the RAID-6 performance with an ARECA controller. It nearly matches the simple read and write speeds, but can not match the performance in database-specific operations like random write or mixed workload.

I'm looking forward to repeat the tests, once the first SSD drives are considered to be stable for enterprise architectures.