Friday, July 31, 2009

ZFS / RAIDZ Benchmarks

At work we needed a new storage/file server as our existing is starting to show sign of aging (it's been running for over 5 years now).

ZFS looked promising on paper. But I had to try.

So I got the following setup.

Lian Li PC343B Cube case, which can host up to 30GB.
Intel 77 920 processor, 6GB DDR3 in triple-channel configuration
Motherboard Gigabyte EX58-UD5P
6 x 2TB Western Digital RE4 drives (RE stands for Raid Edition)

OS Is FreeBSD 8.0-BETA2 (with debugging off) and disks are set in a RAIDZ configuration.

I have to say that so far it's runs quite well, but not as well as I would have thought.
over 275MB/s sequential write, and 310MB/s sequential read...
Invidual disk benchmarks showed that the Western Digital 2TB RE4 could achieve 100MB/s quite easily on its own. Yet, over RAIDZ, that's an average of 45MB/s per disk only.

Typical file server profile with file bench shows in excess of 180MB/s of random access (file server storage). I do not however fully rely on filebench as it had never been ported to FreeBSD and it took me over an hour to get it working on FreeBSD (filebench is a Sun package)

Here is a comparison with our previous file server, which was state of the art 5 years ago (3Ware 9500-S RAID controller,8x74GB 10,000rpm raptor disks, AMD Opteron 248) 98MB/s physical speed

ZFS has passed every attempts to crash it... However, FreeBSD doesn't handle hotplug properly.. So any change of drive due to failure will have to be done with the machine offline unfortunately.

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