Date: Mon, 04 Apr 2011 14:35:33 -0400 From: Graham Todd <gtodd@bellanet.org> To: "J. Hellenthal" <jhell@DataIX.net> Cc: ports@freebsd.org, Urankar Mikael <mikael.urankar@ujf-grenoble.fr>, "Ralf S. Engelschall" <rse@FreeBSD.org> Subject: Re: ZFSv28, zfs list behaviour and sysutils/freebsd-snapshot Message-ID: <4D9A0F75.8000207@bellanet.org> In-Reply-To: <alpine.BSF.2.00.1103140536040.35204@qvfongpu.qngnvk.ybpny> References: <20110310131710.GG96225@iut-mir-o.ujf-grenoble.fr> <alpine.BSF.2.00.1103140225100.90115@qvfongpu.qngnvk.ybpny> <20110314083040.GD47419@iut-mir-o.ujf-grenoble.fr> <alpine.BSF.2.00.1103140536040.35204@qvfongpu.qngnvk.ybpny>
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On 03/14/2011 05:41, J. Hellenthal wrote:
>
> On Mon, 14 Mar 2011 04:30, mikael.urankar@ wrote:
>> On Mon 14 March 2011 at 02:44:16AM -0400, J. Hellenthal wrote:
>>> -----BEGIN PGP SIGNED MESSAGE-----
>>> Hash: SHA1
>>>
>>> On Thu, 10 Mar 2011 08:17, mikael.urankar@ wrote:
>>>> Hi,
>>>>
>>>> I'm using sysutils/freebsd-snapshot to make periodic ZFS backup snapshot
>>>> and this soft is broken since the upgrade of my pool to ZFSv28.
>>>> After some debugging it appears that "zfs list" behaviour has changed
>>>> with ZFSv28, and since freebsd-snapshot relies on "zfs list" to retrieve
>>>> the "ZFS file system name" from the "mountpoint name" the soft doesn't
>>>> work anymore.
>>>>
>>>> output of "zfs list" on a 8.2R amd64 (ZFSv15) :
>>>> zfs list /home/murankar
>>>> NAME USED AVAIL REFER MOUNTPOINT
>>>> tank/home/murankar 1.47M 1.59T 1.47M /home/murankar
>>>>
>>>> zfs list tank/home/murankar
>>>> NAME USED AVAIL REFER MOUNTPOINT
>>>> tank/home/murankar 1.47M 1.59T 1.47M /home/murankar
>>>>
>>>> on a 9-Current amd64 I've got no output for "zfs list /home/murankar"
>>>> and a exit code of 1
>>>> the output of "zfs list tank/home/murankar" is correct :
>>>> NAME USED AVAIL REFER MOUNTPOINT
>>>> tank/home/murankar 6,56G 286G 6,55G /home/murankar
>>>
>>> Looking at the output here I am hoping that this is not hand typed! the
>>> character ',' appears in this output which might fool a script into doing
>>> other things if it has not been avoided in the first place.
>>
>> This is not hand typed and depends on the locale in use :
>>
>> zfs list tank/home/murankar
>> NAME USED AVAIL REFER MOUNTPOINT
>> tank/home/murankar 6,65G 286G 6,58G /home/murankar
>>
>> setenv LANG en_US.UTF8
>> zfs list tank/home/murankar
>> NAME USED AVAIL REFER MOUNTPOINT
>> tank/home/murankar 6.65G 286G 6.58G /home/murankar
>>
>> freebsd-snapshot set LC_ALL and LANG to C
>>
>>> If you have upgraded that machine to 9-CURRENT and have
>>> sysutils/zfsnap installed I would recommend deleting any snapshots
>>> that you have before it runs the snapshot scripts. This assumes that the
>>> snapshot script might have changed since you upgraded it and that the
>>> snapshot names are different. Better to be on the sane side.
>>>
>>> See UPDATING/20100929 for reference.
>>
>> I've deleted all old snapshots before running the snapshot scripts, but
>> to not avail.
>>>
>>> # Correct syntax:
>>> zfs list pool/dataset1/dataset2
>>>
>>> # Incorrect syntax: ( I hope you were hand typing that and missed... )
>>> zfs list /dataset1/dataset2
>>
>> In fact I was only doing by "hand" what freebsd-snapshot is doing.
>> See op_make() from /usr/local/sbin/snapshot (near line 285) :
>>
>> # operate on filesystem
>> + echo "XXX zfs list $fs_dir"
>> if [ ".$zfs_enabled" = .yes ] && (zfs list $fs_dir) >/dev/null
>> 2>&1; then
>>
>> /usr/local/sbin/snapshot make -g4 /var:test
>> XXX zfs list /var
>>>>
>>>> Is it the normal behaviour for ZFSv28 or some kind of regression ?
>>>
>>> No its not normal, and some sort of regression possible. Though I usually
>>> take regression as performance issues as in speed.
>>>
>>> Also,
>>>
>>> pkg-descr
>>> freebsd-snapshot is a set of convenience front-end tools to mount(8)
>>> and mdconfig(8) for the management of UFS2 snapshots. It is
>>> also the under-lying tool used in the periodic snapshot
>>> scheduler periodic-snapshot(8) and the mounting/unmouning
>>> command in the amd(8) map /usr/local/etc/amd.map.snap. It
>>> provides the making, expiring, visiting, mounting and
>>> unmounting of filesystem snapshots.
>>>
>>> pkg-descr
>>> zfSnap is simple sh script to make rolling zfs snapshots with cron. Main
>>> advantage of zfSnap is that it's written in %100 pure /bin/sh, doesn't
>>> require any additional software to run, and is simple to use.
>>>
>>> zfSnap keeps all information about snapshot in snapshot name. zfs snapshot
>>> names are in form: Time-stamp--TTL where time-stamp is date and time of
>>> snapshot creation and TTL is Time To Live in human readable form.
>>>
>>> Did you happen to mix the above two up ? If so then rinse and repeat.
>>
>> Nope, freebsd-snapshot can handle ZFS snapshot and it uses to work fine
>> with ZFSv{14,15}, see the copyright notice :
>> FreeBSD UFS/ZFS Snapshot Management Environment, the pkg-descr file
>> seems outdated.
>>
>> Thanks for your help.
>>
> Since this is s locale dependent script I have added the maintainer to the
> CC so he can adjust it properly upstream.
>
> A simple ( export LC_ALL=C ) to the top of the script should fix it
> permanently.
Sorry for late response. I do not have access to CURRENT or a ZFSv28 just
now but there is a patch in the port (files/patch-snapshot) that sets the
locale to C for compatibility. It's in the install from ports that I use:
egrep -i LC_\|LANG /usr/local/sbin/snapshot
LC_ALL=C
LANG=C
Not sure what the error might come from otherwise. I agree an updated
description should indicate the ZFS features of freebsd-snapshot. I will
submit something as a port patch. Maybe:
+++
freebsd-snapshot is a snapshot management tool for UFS2 only, ZFS only,
and "mixed" systems - one that you can keep on using even as you switch
file systems and layouts. freebsd-snapshot provides a uniform interface
for all snapshots and simplifies administration if you have a mix of file
system types.
+++
Do you have any other suggested changes? Maybe for convenience "snapshot
list" could indicate whether a snapshot derives from a ZFS or a UFS file
system without requiring the -v flag? Perhaps better documentation of
behaviours when a snapshot is ZFS or USF2 based would be helpful. E.g. the
"mount" "visit" "umount" are sub-commands are either redundant or do
different things if one is using ZFS or UFS2. The script could maybe
catch when umount is used for a snapshot that does exist but does not
require umount'ing and does not use md(4) (i.e. ZFS snapshots - currently
I think that case emits a misleading error message? I can't recall exactly
but I remember noticing this once). Mostly quite small changes are all I
can think off. Maybe tarsnap integration ? ;-D
Of course a lot of functionality is getting "built-in" to zfs and related
zfs only scripts, and I am not sure how much more development or what
direction Ralf has planned for his freebsd-snapshot tool. My impression
is that *lots* of people are still using UFS2. If SUJ becomes the default
for 9.0, UFS2 could soldier on for a long time - even on TB+ file systems
- so this simple but excellent tool will remain very useful.
cheers,
G.Todd
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