I recently created a raidz of four 2TB-disks and moved a bunch of movies onto them. And then I noticed that I''ve somehow lost a full TB of space. Why? nebol at filez:/$ zfs list tank2 NAME USED AVAIL REFER MOUNTPOINT tank2 3.12T 902G 32.9K /tank2 nebol at filez:/$ zpool list tank2 NAME SIZE USED AVAIL CAP HEALTH ALTROOT tank2 5.44T 4.18T 1.26T 76% ONLINE - I know that ZFS needs space for meta-data, but a full TB ??? -- This message posted from opensolaris.org
On Mon, Jun 6, 2011 at 3:39 PM, Johan Eliasson <johan.eliasson.jobb at gmail.com> wrote:> I recently created a raidz of four 2TB-disks and moved a bunch of movies onto them. > And then I noticed that I''ve somehow lost a full TB of space. Why?zpool reports space usage on disks, without taking into account RAIDZ overhead. zfs reports net capacity available, after RAIDZ overhead accounted for.> > nebol at filez:/$ zfs list tank2 > NAME ? ?USED ?AVAIL ?REFER ?MOUNTPOINT > tank2 ?3.12T ? 902G ?32.9K ?/tank2 > > nebol at filez:/$ zpool list tank2 > NAME ? ?SIZE ? USED ?AVAIL ? ?CAP ?HEALTH ?ALTROOT > tank2 ?5.44T ?4.18T ?1.26T ? ?76% ?ONLINE ?- > > I know that ZFS needs space for meta-data, but a full TB ??? > -- > This message posted from opensolaris.org > _______________________________________________ > zfs-discuss mailing list > zfs-discuss at opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss >-- Regards, ? ? ? ? Cyril
On 06/06/11 08:07, Cyril Plisko wrote:> zpool reports space usage on disks, without taking into account RAIDZ overhead. > zfs reports net capacity available, after RAIDZ overhead accounted for.Yup. Going back to the original numbers: nebol at filez:/$ zfs list tank2 NAME USED AVAIL REFER MOUNTPOINT tank2 3.12T 902G 32.9K /tank2 Given that it''s a 4-disk raidz1, you have (roughly) one block of parity for every three blocks of data. 3.12T / 3 = 1.04T so 3.12T + 1.04T = 4.16T, which is close to the 4.18T showed by zpool list: NAME SIZE USED AVAIL CAP HEALTH ALTROOT tank2 5.44T 4.18T 1.26T 76% ONLINE
I see now that a detail in my first post was incorrect, one of the disks is a 1.5 TB-disk, so the pool is thus 4 x 1.5 TB. So zpool reports total space including parity. It makes sense then! Thanks! -- This message posted from opensolaris.org