ZFS Stability & MySQL (Comments Requested)

[Eirik Øverby]

Hi,

just chirping in; we've upgraded a bunch of old 6.x servers to 8.0 with ZFS. This is a pair of HP DL385 G1s (dual opteron, old stuff) with SmartArray controllers, which had absolutely horrible performance in both 6.0 and 8.0. The drive array gave us ~25 mbyte/s sustained, which is obviously abysmal for U320/15k SCSI drives backed by hardware RAID and cache.

We ended up splitting the hardware RAID into single drives, and using ZFS/RaidZ. We suddenly got around 45 mbye/s (still bad) per channel, adding up nicely when benchmarking the RaidZ volume.

MySQL now performs much better than before, and we've enabled compression (gzip-2) and fixed block sizes. Compression ratio is about 1.7:1, transaction latency on the database (as seen from application) has gone down by about 65% on average.

We see anything between 300 and 2000 queries/second throughout the day, and our active dataset is about 500GB. The servers have 8GB of memory.

/Eirik

On Apr 29, 2010, at 4:31 PM, Jason J. W. Williams wrote:

> Hi Y'all,
> 
> I've written before that we're considering moving to FreeBSD 8 from
> OpenSolaris and are heavily reliant on ZFS. Has anyone used FreeBSDs
> ZFS implementation for a high reliability environment like a database?
> If so, what are your experiences?
> 
> Basically, I'm curious how stable the implementation is and whether
> it's ready for a critical production environment. Also, any gotchas
> particularly with running it with MySQL or anything else that utilizes
> a lot of memory. On Solaris, we cap the max ARC size to keep it from
> grabbing all the system RAM and competing with MySQL.
> 
> Any thoughts or comments are greatly appreciated.
> 
> -J
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