On Oct 24, 2006, at 04:19, Roch wrote:
Michel Kintz writes:
Matthew Ahrens a écrit :
Richard Elling - PAE wrote:
Anthony Miller wrote:
Hi,
I've search the forums and not found any answer to the following.
I have 2 JBOD arrays each with 4 disks.
I want to create create a raidz on one array and have it
mirrored to
the other array.
Today, the top level raid sets are assembled using dynamic
striping.
There
is no option to assemble the sets with mirroring. Perhaps the ZFS
team can
enlighten us on their intentions in this area?
Our thinking is that if you want more redundancy than RAID-Z, you
should use RAID-Z with double parity, which provides more
reliability
and more usable storage than a mirror of RAID-Zs would.
(Also, expressing "mirror of RAID-Zs" from the CLI would be a bit
messy; you'd have to introduce parentheses in vdev descriptions or
something.)
It is not always a matter of more redundancy.
In my customer's case, they have storage in 2 different rooms of
their
datacenter and want to mirror from one storage unit in one room to
the
other.
So having in this case a combination of RAID-Z + Mirror makes
sense in
my mind .... or ?
Michel.
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you may let the storage export RAID-5 luns and let ZFS
mirror those. Would that work ?
-r
they're JBOD arrays, so unless you're proposing the use of another
volume manager i don't think that would work. as for the maximum
redundancy in configurations, i think that Frank hit it with the
mirroring
of each drive component across the arrays and doing a simple stripe
I just think it would be good to add the flexibility in zpool to:
1) raidz a set of mirrors
2) mirror a couple of raidz
in certain environments you care more about multiple drive or array
failures than anything else.
Today you can do this with zvols, but I'm a little worried about how
this
would perform given the nested layering you have to introduce .. eg:
# zpool create a1pool raidz c0t0d0 c0t1d0 c0t2d0 ..
# zpool create a2pool raidz c1t0d0 c1t1d0 c1t2d0 ..
# zfs create -V <size> a1pool/vol
# zfs create -V <size> a2pool/vol
# zpool create mzdata mirror /dev/zvol/dsk/a1pool/vol /dev/zvol/dsk/
a2pool/vol
.je
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