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> 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 -- This message has been scanned for viruses and dangerous content by <http://www.mailscanner.info/> MailScanner, and is believed to be clean. _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
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