Best practices for ZFS setup for a strictly SSD based system?

Patrick M. Hausen hausen at punkt.de
Tue Feb 9 17:05:25 UTC 2016


Hi!

> Am 09.02.2016 um 17:32 schrieb Alan Somers <asomers at freebsd.org>:
> [...]
> http://blog.delphix.com/matt/2014/06/06/zfs-stripe-width/
> 
>> 
>> *       Will e.g. MySQL still profit from residing on a mirror
>>        instead of a RAIDZ2, even if all disks are SSDs?
> 
> Yes, because a mirrored vdev has as many read IOPs as all of its disks
> combined.  So a RAID10 of SSDs will have many read IOPs indeed.

Ah … yes. Now I remember :)

> […]
> Will MySQL access its files in fixed-size records?  If so, you can set
> the recsize filesystem property accordingly.  If not, you should
> probably leave recsize at the default.  If you profile MySQL's disk
> accesses and determine that there is a dominant recordsize, then go
> ahead and set ZFS's recsize to the next highest power of two.
> 
> As usual, disable atime.

We already knew these. But thanks a lot for the vdev setup
hints! So it will be a mirror for OS and DB and a 4+2 raidz2
for the rest of the data.

Our MySQL zvols are currently set up like this:

DB files:
	recordsize=16k
	atime=off
	primarycache=metadata

InnoDB log files:
	recordsize=128k
	(rest inherited from above)

Kind regards,
Patrick
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