[OpenIndiana-discuss] Finding the "last" snapshot for a zfs volume

[Discussion list for OpenIndiana]

I have a backup script that locates the snapshot name of the last snapshot
on the single filesystem like so:

zfs list -H -d 1 -o name -S creation -t snapshot "$target" | head -n 1 |
cut -f2 -d@

(actually, I have another grep in the chain that only looks for backup
snapshots)

The "$target" points it at a single filesystem, -S creation means sort by
creation time, -H means don't print the column headers, -d 1 (depth 1) and
-t snapshot combine to list only the snapshots of that filesystem.  The
head gets the first, being most recent, and the cut strips the filesystem
name, leaving only the snapshot name.

Tim



On Mon, May 12, 2014 at 6:48 AM, Discussion list for OpenIndiana <
openindiana-discuss at openindiana.org> wrote:

> Most of my systems I do "zfs list -t snapshot > file" then grep that file
> of each of the filesystems I am interested in.
>
> John
>
> -----Original Message-----
> From: Discussion list for OpenIndiana [mailto:
> openindiana-discuss at openindiana.org]
> Sent: 12 May 2014 12:20
> To: Discussion list for OpenIndiana
> Subject: [OpenIndiana-discuss] Finding the "last" snapshot for a zfs volume
>
> On our backup servers I have a "backup-check" script that checks to see
> what the last snapshot for a particular volume is (and compares it with the
> current date)
>
> df -F zfs -h |grep $mypool | nawk '{system("zfs list -t snapshot -r "$1"
> \| tail -1")}' | egrep -v "$yesterday|no datasets"
>
> okay, it's messy, but it should find the last snapshot for each zfs slice
> within a pool.
>
> However with the number of pools on the server increasing, and the number
> of snapshots getting bigger every day, I was wondering if there is an
> easier way of getting the latest snapshot than "zfs list -t snapshot -r
> pool/snapshot | tail -1"
>
> Any ideas would be helpful.
>
> Jon
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