Roman Naumenko
2009-Nov-04 14:26 UTC
[zfs-discuss] zfs usedbysnapshots is not equial to "zfs list -t snapshot" for a filesyste
This is on Opensolaris 118b # zfs get all torstor/tor/fs NAME PROPERTY VALUE SOURCE torstor/tor/fs type volume - torstor/tor/fs creation Wed May 13 17:57 2009 - torstor/tor/fs used 1.51T - torstor/tor/fs available 5.19T - torstor/tor/fs referenced 1.35T - torstor/tor/fs compressratio 1.00x - torstor/tor/fs reservation none default torstor/tor/fs volsize 3T - torstor/tor/fs volblocksize 128K - torstor/tor/fs copies 1 default torstor/tor/fs refreservation none default torstor/tor/fs usedbysnapshots 161G - torstor/tor/fs usedbydataset 1.35T - torstor/tor/fs usedbychildren 0 - torstor/tor/fs usedbyrefreservation 0 - torstor/tor/fs at zfs-auto-snap:tor_fs-2009-10-26-00:00 19.4G torstor/tor/fs at zfs-auto-snap:tor_fs-2009-10-27-00:00 3.79G torstor/tor/fs at zfs-auto-snap:tor_fs-2009-10-28-00:00 8.95G torstor/tor/fs at zfs-auto-snap:tor_fs-2009-10-29-00:00 3.93G torstor/tor/fs at zfs-auto-snap:tor_fs-2009-10-30-00:00 4.38G torstor/tor/fs at zfs-auto-snap:tor_fs-2009-10-31-00:00 1.84G torstor/tor/fs at zfs-auto-snap:tor_fs-2009-11-01-00:00 886M torstor/tor/fs at zfs-auto-snap:tor_fs-2009-11-02-00:00 1.09G torstor/tor/fs at zfs-auto-snap:tor_fs-2009-11-03-00:00 5.08G torstor/tor/fs at zfs-auto-snap:tor_fs-2009-11-04-00:00 1.68G The total space occupied by snapshots from the second print is far less than reported in the first (usedbysnapshots 161G) Why is there so big difference? -- Roman Naumenko roman at frontline.ca -- This message posted from opensolaris.org
Anton B. Rang
2009-Nov-04 15:15 UTC
[zfs-discuss] zfs usedbysnapshots is not equial to "zfs list -t snapshot" for a files
I believe that space shared between multiple snapshots is not assigned to any of the snapshots. So if you have a 100 GB file and take two snapshots, then delete it, the space used won''t show up in the snapshot list, but will show up in the ''usedbysnapshots'' property. -- This message posted from opensolaris.org
Roman Naumenko
2009-Nov-04 16:13 UTC
[zfs-discuss] zfs usedbysnapshots is not equial to "zfs list -t snapshot" for a files
Not sure what you mean. Can I ask for more detailed explanation? Is anybody else see the difference in snapshots size on own file-systems? I mean the difference between "zfs list -t snapshot" and "zfs list -o space" Roman Naumenko roman at frontline.ca -- This message posted from opensolaris.org
Miles Nordin
2009-Nov-05 20:12 UTC
[zfs-discuss] zfs usedbysnapshots is not equial to "zfs list -t snapshot" for a filesyste
>>>>> "rn" == Roman Naumenko <roman at frontline.ca> writes:rn> The total space occupied by snapshots from the second print is rn> far less than reported in the first (usedbysnapshots 161G) It will take me too much thinking to untangle this sentence, but maybe you can untangle mine: The space ``used'''' by a snapshot is the amount of free space you will gain by deleting the snapshot. If you delete one snapshot, the used values for all the other snapshots will reshuffle. so, you can''t add the numbers like that. In a fantasy world where you take infinitely many snapshots their used columns would all say zero. You could also make the column all-zeroes by always taking pairs of snapshots. rn> Why is there so big difference? play around with it a bit and see. I mean, make an empty filesystem and use space on it on purpose around your test, instead of just looking at the output resulting from haphazard actions and saying wtfconfused. -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 304 bytes Desc: not available URL: <http://mail.opensolaris.org/pipermail/zfs-discuss/attachments/20091105/33b89d05/attachment.bin>