Leon,
RAIDZ2 is ~equivalent to RAID6. ~2 disks of parity data. Allowing a
double drive
failure and still having the pool available.
If possible though you would be best to let the 3ware controller expose
the 16 disks as a JBOD to ZFS and create a RAIDZ2 within Solaris as you
will then
gain the full benefits of ZFS. Block self healing etc etc.
There isn't an issue in using a larger amount of disks in a RAIDZ2, just
that it
is not the optimal size. Longer rebuild times for larger vdev's in a
zpool (although this
is proportional to how full the pool is.). Two parity disks gives you
greater cover in
the event of a drive failing in a large vdev stripe.
/Scott
Leon Meßner wrote:
Hi,
i'm new to the list so please bare with me. This isn't an OpenSolaris
related problem but i hope it's still the right list to post to.
I'm on the way to move a backup server to using zfs based storage, but i
don't want to spend too much drives to parity (the 16 drives are attached
to a 3ware raid controller so i could also just use raid6 there).
I want to be able to sustain two parallel drive failures so i need
raidz2. The man page of zpool says the recommended vdev size is
somewhere between 3-9 drives (for raidz). Is this just for getting the
best performance or are there stability issues ?
There won't be anything like heavy multi-user IO on this machine so
couldn't i just put all 16 drive in one raidz2 and have all the benefits
of zfs without sacrificing 2 extra drives to parity (compared to raid6)?
Thanks in Advance,
Leon
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_______________________________________________________________________
Scott Lawson
Systems Architect
Manukau Institute of Technology
Information Communication Technology Services Private Bag 94006 Manukau
City Auckland New Zealand
Phone : +64 09 968 7611
Fax : +64 09 968 7641
Mobile : +64 27 568 7611
mailto:sc...@manukau.ac.nz
http://www.manukau.ac.nz
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perl -e 'print
$i=pack(c5,(41*2),sqrt(7056),(unpack(c,H)-2),oct(115),10);'
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