Hi there,

I've created a diy SAN on Centos/Linux to serve a Mac editing (audio video) workstation. I am experiencing performance problems and was wondering if anyone is able to help me.

I have the following setup:
2 x 500Gb SATA drives, software mirrored (mdadm) and created a Logical Volume on top of them. I thus have a 500Gig redundant volume.
I serve this volume using iscsi-target over a Gigabit (Intel Pro) NIC.

Currently my throughput is 10 - 12 MBytes per second. If I use MTU=1500, the throughput = 10MB. If I use MTU=9000, the throughput is 12MB.

I expect performance problems in the following areas:

1. Network performance.
2. SATA performance.

There isn't much help on this topic out there, and I was hoping that people with experience in this area could help me to not only solve my problem, but maybe help others too.

I expected to get at least 40 - 50 MB per second. Since the Gigabit should give me at least 45MB per second, and the SATA single drive should give me at least 50MB per second. Am I correct in assuming these? The CPU runs at +- 70% when fully loaded (with IO), of which 50% is waitio.

Any help would be appreciated.