Date: Fri, 3 Feb 2017 12:42:51 +0000 From: Gary Palmer <gpalmer@freebsd.org> To: Ultima <ultima1252@gmail.com> Cc: freebsd-stable@freebsd.org, freebsd-current@freebsd.org, freebsd-fs@freebsd.org Subject: Re: zfs snapshot_limit is not respected Message-ID: <20170203124251.GA68015@in-addr.com> In-Reply-To: <CANJ8om7HKhXB8RoaisBay-L70EzLDSBmiV_fnJqBOwohrCC3sQ@mail.gmail.com> References: <CANJ8om7HKhXB8RoaisBay-L70EzLDSBmiV_fnJqBOwohrCC3sQ@mail.gmail.com>
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On Thu, Feb 02, 2017 at 09:31:58PM -0500, Ultima wrote:
> I recently moved some data on a box with limited space. I decided I should
> limit the snapshots so that space would not become an issue. I just check
> back a week later to find out the box is hitting the borderline. Doing I
> quick check I realized that the snapshot_limit is not being respected.
>
> # uname -a
> FreeBSD R1 11.0-STABLE FreeBSD 11.0-STABLE #17 r312232: Sun Jan 15 10:59:10
> EST 2017 root@S1:/usr/src/11-STABLE/obj/usr/src/11-STABLE/src/sys/MYKERNEL
> amd64
>
> # zfs create zroot/bhyve/test
> # zfs set snapshot_limit=0 zroot/bhyve/test
> # zfs snapshot zroot/bhyve/test@1
>
>
> # zfs snapshot zroot/bhyve/test@2
> # zfs snapshot zroot/bhyve/test@3
> # zfs list -t snapshot | grep zroot/bhyve/test
> zroot/bhyve/test@1 0 -
> 88K -
> zroot/bhyve/test@2 0 -
> 88K -
> zroot/bhyve/test@3 0 -
> 88K -
> # zfs get all zroot/bhyve/test | grep snapshot
> zroot/bhyve/test usedbysnapshots 0 -
> zroot/bhyve/test snapshot_limit 0 local
> zroot/bhyve/test snapshot_count 3 local
>
> Also wanted to verify 0 was not being mistaken for none.
>
> # for snapshot in `zfs list -t snapshot | grep zroot/bhyve/test | awk
> '{print $1}'`; do zfs destroy $snapshot ; done
>
> # zfs get all zroot/bhyve/test | grep snapshot
> zroot/bhyve/test usedbysnapshots 0 -
> zroot/bhyve/test snapshot_limit 0 local
> zroot/bhyve/test snapshot_count 0 local
>
> # zfs set snapshot_limit=1 zroot/bhyve/test
> # zfs snapshot zroot/bhyve/test@1
> # zfs snapshot zroot/bhyve/test@2
> # zfs snapshot zroot/bhyve/test@3
> # zfs get all zroot/bhyve/test | grep snapshot
> zroot/bhyve/test usedbysnapshots 0 -
> zroot/bhyve/test snapshot_limit 1 local
> zroot/bhyve/test snapshot_count 3 local
>
>
> Also tested on head
> FreeBSD S1 12.0-CURRENT FreeBSD 12.0-CURRENT #26 r312388: Wed Jan 18
> 12:38:52 EST 2017
> root@S1:/usr/src/head/obj/usr/src/head/src/sys/MYKERNEL-NODEBUG
> amd64
Hi,
I suspect this line from the manpage is key:
The limit is not enforced if the user is allowed to change the limit
Regards,
Gary
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