Hi Ned,
If you look at the examples on the page that you cite, they start
with single-parity RAIDZ examples and then move to double-parity RAIDZ
example with supporting text, here:
http://docs.sun.com/app/docs/doc/819-5461/gcvjg?a=view
Can you restate the problem with this page?
Thanks,
Cindy
On 03/26/10 05:42, Edward Ned Harvey wrote:
Just because most people are probably too lazy to click the link, I’ll
paste a phrase from that sun.com webpage below:
“Creating a single-parity RAID-Z pool is identical to creating a
mirrored pool, except that the ‘raidz’ or ‘raidz1’ keyword is used
instead of ‘mirror’.”
And
“zpool create tank raidz2 c1t0d0 c2t0d0 c3t0d0”
So … Shame on you, Sun, for doing this to your poor unfortunate
readers. It would be nice if the page were a wiki, or somehow able to
have feedback submitted…
*From:* zfs-discuss-boun...@opensolaris.org
[mailto:zfs-discuss-boun...@opensolaris.org] *On Behalf Of *Bruno Sousa
*Sent:* Thursday, March 25, 2010 3:28 PM
*To:* Freddie Cash
*Cc:* ZFS filesystem discussion list
*Subject:* Re: [zfs-discuss] RAIDZ2 configuration
Hmm...it might be completely wrong , but the idea of raidz2 vdev with 3
disks came from the reading of
http://docs.sun.com/app/docs/doc/819-5461/gcvjg?a=view .
This particular page has the following example :
*zpool create tank raidz2 c1t0d0 c2t0d0 c3t0d0*
# *zpool status -v tank*
pool: tank
state: ONLINE
scrub: none requested
config:
NAME STATE READ WRITE CKSUM
tank ONLINE 0 0 0
raidz2 ONLINE 0 0 0
c1t0d0 ONLINE 0 0 0
c2t0d0 ONLINE 0 0 0
c3t0d0 ONLINE 0 0 0
So...what am i missing here? Just a bad example in the sun documentation
regarding zfs?
Bruno
On 25-3-2010 20:10, Freddie Cash wrote:
On Thu, Mar 25, 2010 at 11:47 AM, Bruno Sousa <bso...@epinfante.com
<mailto:bso...@epinfante.com>> wrote:
What do you mean by "Using fewer than 4 disks in a raidz2 defeats the
purpose of raidz2, as you will always be in a degraded mode" ? Does it
means that having 2 vdevs with 3 disks it won't be redundant in the
advent of a drive failure?
raidz1 is similar to raid5 in that it is single-parity, and requires a
minimum of 3 drives (2 data + 1 parity)
raidz2 is similar to raid6 in that it is double-parity, and requires a
minimum of 4 drives (2 data + 2 parity)
IOW, a raidz2 vdev made up of 3 drives will always be running in
degraded mode (it's missing a drive).
--
Freddie Cash
fjwc...@gmail.com <mailto:fjwc...@gmail.com>
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