ZFS ZFS and SANs

[tanked]

Hello, I was wondering if anyone has experience using ZFS with SANs - given that ZFS prefers to have direct access to the physical disks how would you configure it with SAN storage? If you were to present the disks to ZFS, would that mean you would not be able to take advantage of SAN features such as NVRAM etc.?

 

[mav@]

SAN needlessly duplicates part of ZFS functionality related to fault-tolerance. If you trust your SAN enough -- feel free to use it. But if SAN miss some data corruption, ZFS may not be able to fix it due to lack of redundancy. NVRAM is good too -- it can reduce write latency. ZFS usually does that itself by dedicated SLOG device, but I don't think it get offended.

 

[robroy]

Good day Tanked!

mav@'s reply is better than mine, but I thought I'd post anyways since I have experience with something similar.

I use FreeBSD backed by SAN storage every day, though ESX and VMFS are sandwiched in between FreeBSD and the SAN since it's running in a VM.

It's configured with a root-on-ZFS install based on a mirror across two ESX virtual disks--one resides upon a VMFS filesystem based on an LU from a Hitachi HUS Modular array, and the other upon a separate VMFS based on an LU from a Hitachi AMS Modular. This protects my toy in case one or the other array gets smashed or wheeled out of the building one day.

No special configuration was needed for this to work well, though ESX and VMFS in the middle's different from a FreeBSD host with direct SAN connections (which is what you're really asking about, I believe).