Hello Sanjeev, Wednesday, December 3, 2008, 5:20:47 AM, you wrote:
S> Hi, S> A good rough estimate would be the total of the space S> that is displayed under the "USED" column of "zfs list" for those snapshots. S> Here is an example : S> -- snip -- S> [EMAIL PROTECTED] zfs list -r tank S> NAME USED AVAIL REFER MOUNTPOINT S> tank 24.6M 38.9M 19K /tank S> tank/fs1 24.4M 38.9M 18K /tank/fs1 S> tank/[EMAIL PROTECTED] 24.4M - 24.4M - S> -- snip -- S> In the above case tank/[EMAIL PROTECTED] is using 24.4M. So, if we delete S> that snapshot it would freeup about 24.4M. Let's delete it an S> see what we get : S> -- snip -- S> [EMAIL PROTECTED] zfs destroy tank/[EMAIL PROTECTED] S> [EMAIL PROTECTED] zfs list -r tank S> NAME USED AVAIL REFER MOUNTPOINT S> tank 220K 63.3M 19K /tank S> tank/fs1 18K 63.3M 18K /tank/fs1 S> -- snip -- S> So, we did get back 24.4M freed (39.9M + 24.4M = 63.3M). S> Note that this could get a little complicated if there are multiple S> snapshots which refer to the same set of blocks. So, even after deleting S> one snapshot you might not see the space freed up. And this could be because, S> of the second snapshot which is refering to some of the blocks still. That's what I meant by: >> I'm afraid you can do only one at a time. The problem is that once you got several snapshots and you want to calculate how much space you will re-gain if you delete two (or more) of them - you just can't calculate it by looking at zfs list output. All you can say is how much space at least you will re-gain which is summary of used column for snapshots to be deleted - but if they share some blocks then you might or might not (depends if yet other snapshots share some of these shared blocks) re-gain much more. -- Best regards, Robert Milkowski mailto:[EMAIL PROTECTED] http://milek.blogspot.com _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
