Hi Cindy, This all issue started when i asked opinion in this list in how should i create zpools. It seems that one of my initial ideas of creating a vdev with 3 disks in a raidz configuration seems to be a non-sense configuration. Somewhere along the way i "defended" my initial idea with the fact that the documentation from Sun has as an example such configuration as seen here :
*zpool create tank raidz2 c1t0d0 c2t0d0 c3t0d0* at http://docs.sun.com/app/docs/doc/819-5461/gcvjg?a=view So if by concept the idea of having a vdev with 3 disks within a raidz configuration is a bad one, the oficial Sun documentation should not have such example. However if people made such example in Sun documentation, perhaps this all idea is not that bad at all.. Can you provide anything on this subject? Thanks, Bruno On 31-3-2010 23:49, Cindy Swearingen wrote: > 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> >> >> -- >> This message has been scanned for viruses and >> dangerous content by *MailScanner* <http://www.mailscanner.info/>, >> and is >> believed to be clean. >> >> >> >> >> >> _______________________________________________ >> >> zfs-discuss mailing list >> >> zfs-discuss@opensolaris.org <mailto:zfs-discuss@opensolaris.org> >> >> http://mail.opensolaris.org/mailman/listinfo/zfs-discuss >> >> >> >> >> >> ------------------------------------------------------------------------ >> >> _______________________________________________ >> zfs-discuss mailing list >> zfs-discuss@opensolaris.org >> http://mail.opensolaris.org/mailman/listinfo/zfs-discuss > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss >
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