On Mon, Jan 12, 2009 at 3:23 PM, Brian Hechinger <wo...@4amlunch.net> wrote:
> I've got a server at home that I'm about to set up. I'll be moving 3x 500GB
> SATA
> disks into it from a different machine, so the config of those is set. What
> I need
> help with is the other disks. I'm not sure what the best way to use them is.
>
> I want to do ZFS Boot, so I'm limited to what config I can use for these
> other disks.
>
> I have 4x 73GB 15K rpm SAS disks. I'll need to run at least two of them in a
> mirror
> for the OS. The question is, how do I use the other two? I'd like to at
> least use
> them for ZIL, and possibly L2ARC, but the question is this:
>
> Am I better off running drives 3 and 4 as a mirror for ZIL/L2ARC or am I
> better off
> using the SAS controller to create two stripes of two disks each and then use
> ZFS to
> mirror what's left over, leaving space for ZIL/L2ARC.
>
> Thoughts?
>
> -brian
Hi Brian,
I tried running with one 146Gb 15k SAS disk for Zil and a 2nd
(identical) disk for L2ARC and it turns out to be a "bad" use of that
hardware. "Bad" is a highly subjective assessment, based on the type
of workload you're running and your expectations - but, for my money,
those disks would be better utilized as another zfs mirror - or as
members of a stipe as you've specified above. There is also the bug
with removing the drives from the zpool if you change your mind (you
can only remove the cache drive right now IIRC).
IMHO it makes more sense to add RAM to the system (if possible) in
order to get the best performance from ZFS - or wait until the
price/performance of SSDs make them a compelling buy.
Regards,
--
Al Hopper Logical Approach Inc,Plano,TX a...@logical-approach.com
Voice: 972.379.2133 Timezone: US CDT
OpenSolaris Governing Board (OGB) Member - Apr 2005 to Mar 2007
http://www.opensolaris.org/os/community/ogb/ogb_2005-2007/
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