Mar 012012
We always use QLogic Fibre Channel Switches for our SAN installation. These switches have some options to increase throughput and decrease spikes during large file transfers, namely I/O Stream Guard and Device Scan.
It’s quite important to set this options correct for a good overall performance of the SAN regardless of the used software (XSan, metaSAN, HyperFS, …).
Here’s what you have to use:
Initiators (your clients)
I/O Stream Guard: Enabled
Device Scan: Disabled
Target (your RAIDs)
I/O Stream Guard: Disable
Device Scan: Enabled
Apple also posted a KB article a few years ago about this topic.