Date: Fri, 20 Dec 2013 10:19:15 +0100 (CET) From: krichy@tvnetwork.hu To: =?ISO-8859-15?Q?Gerrit_K=FChn?= <gerrit.kuehn@aei.mpg.de> Cc: freebsd-fs@freebsd.org Subject: Re: ZFS snapshot renames failing after upgrade to 9.2 Message-ID: <alpine.DEB.2.10.1312201010350.12244@krichy.tvnetwork.hu> In-Reply-To: <20131220100522.382a39ac.gerrit.kuehn@aei.mpg.de> References: <0C9FD4E1-0549-4849-BFC5-D8C5D4A34D64@msqr.us> <54D3B3C002184A52BEC9B1543854B87F@multiplay.co.uk> <333D57C6A4544067880D9CFC04F02312@multiplay.co.uk> <26053_1387447492_52B2C4C4_26053_331_1_20131219105503.3a8d1df3.gerrit.kuehn@aei.mpg.de> <20131219165549.9f2ca709.gerrit.kuehn@aei.mpg.de> <alpine.DEB.2.10.1312191718330.12885@krichy.tvnetwork.hu> <20131219174054.91ac617a.gerrit.kuehn@aei.mpg.de> <alpine.DEB.2.10.1312192007100.30378@krichy.tvnetwork.hu> <20131220100522.382a39ac.gerrit.kuehn@aei.mpg.de>
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[-- Attachment #1 --]
Dear Gerrit,
It is not a solution, but I use different snapshot handling mechanisms. I
wrote a simple script which handles that, and the snapshots are named by
its creation timestamp. I think it is more usable to see that when that
snapshot was exactly taken, and the script thus only does snapshot
creation, and deletion, no renames.
That scripts only limitation is that it is planned to run hourly, creating
hourly snapshots, and when run again, it queries the existing one's list,
and decides which to keep or remove. Thus you have to run it hourly in
cron like:
# crontab -l
0 * * * * /usr/local/sbin/zfs-snapshot
Regards,
Kojedzinszky Richard
Euronet Magyarorszag Informatikai Zrt.
On Fri, 20 Dec 2013, Gerrit Kühn wrote:
> Date: Fri, 20 Dec 2013 10:05:22 +0100
> From: Gerrit Kühn <gerrit.kuehn@aei.mpg.de>
> To: krichy@tvnetwork.hu
> Cc: freebsd-fs@freebsd.org
> Subject: Re: ZFS snapshot renames failing after upgrade to 9.2
>
> On Thu, 19 Dec 2013 20:08:22 +0100 (CET) krichy@tvnetwork.hu wrote about
> Re: ZFS snapshot renames failing after upgrade to 9.2:
>
> KH> So a simple renaming can cause your system to hang?
>
> No, it does not hang completely.
> Just the snapshots become unusable. This night, it happened again:
>
> ---
> root@shapeshifter:~ # ll /tank/git/.zfs/snapshot/
> ls: daily.6: Device busy
> total 33
> drwxr-xr-x 12 211 211 25 Dec 19 09:18 daily.0/
> drwxr-xr-x 12 211 211 25 Dec 19 00:00 daily.1/
> drwxr-xr-x 12 211 211 24 Dec 18 00:00 daily.2/
> drwxr-xr-x 12 211 211 24 Dec 17 00:00 daily.3/
> drwxr-xr-x 12 211 211 24 Dec 16 00:00 daily.4/
> drwxr-xr-x 12 211 211 24 Dec 14 00:00 daily.5/
> drwxr-xr-x 12 211 211 24 Dec 15 00:00 weekly.0/
> drwxr-xr-x 12 211 211 24 Dec 8 00:00 weekly.1/
> drwxr-xr-x 12 211 211 24 Dec 1 00:00 weekly.2/
> drwxr-xr-x 12 211 211 24 Nov 17 00:00 weekly.3/
> drwxr-xr-x 12 211 211 24 Nov 10 00:00 weekly.4/
> drwxr-xr-x 2 root wheel 3 Oct 20 00:00 weekly.5/
> drwxr-xr-x 2 root wheel 3 Oct 6 00:00 weekly.6/
> ---
>
> root@shapeshifter:~ # zfs list -r -t snapshot -o
> name,creation,used,referenced tank/git NAME
> CREATION USED REFER tank/git@weekly.6 Sun Oct 6 0:00
> 2013 42.6K 62.8K tank/git@weekly.5 Sun Oct 20 0:00 2013 42.6K 62.8K
> tank/git@weekly.4 Sun Nov 10 0:00 2013 29.5M 146G
> tank/git@weekly.3 Sun Nov 17 0:00 2013 27.1M 146G
> tank/git@weekly.2 Sun Dec 1 0:00 2013 26.3M 146G
> tank/git@weekly.1 Sun Dec 8 0:00 2013 27.3M 146G
> tank/git@daily.6 Sat Dec 14 0:00 2013 26.5M 147G
> tank/git@weekly.0 Sun Dec 15 0:00 2013 25.2M 147G
> tank/git@daily.5 Mon Dec 16 0:00 2013 24.7M 147G
> tank/git@daily.4 Tue Dec 17 0:00 2013 24.9M 147G
> tank/git@daily.3 Wed Dec 18 0:00 2013 25.7M 147G
> tank/git@daily.2 Thu Dec 19 0:00 2013 25.8M 147G
> tank/git@daily.1 Thu Dec 19 9:19 2013 25.0M 147G
> tank/git@daily.0 Fri Dec 20 0:00 2013 26.8M 147G
> ---
>
>
> As you can see, the snapshot rotating got stuck somewhere. What is
> displayed under .zfs/snapshot does not reflect what zfs is really seeing:
> daily.6 is inaccessible, and the rotation that happened so far is not
> reflected under .zfs/snapshot, either.
>
>
> cu
> Gerrit
>
[-- Attachment #2 --]
#!/bin/sh
unset LANG
export PATH=/bin:/sbin:/usr/bin:/usr/sbin
# configuration
datasets="root/root pool/home pool/usr"
hourly_keep=168
daily_keep=90
weekly_keep=106
# override dataset-specific keep times
root_root_hourly_keep=48
root_root_daily_keep=30
root_root_weekly_keep=8
# configuration ends
stamp=$(date +%Y%m%d%H00)
ee ()
{
logger -t "zfs-snapshot" "executing $@"
eval "$@"
}
get_keep ()
{
local dset="$1"
local period="$2"
local r
eval "r=\$$(echo "$dset" | sed -e "s#[/-]#_#g")_${period}_keep"
if [ -z "$r" ]; then
eval "r=\$${period}_keep"
fi
echo "$r"
}
for set in $datasets ; do
sn="$set@auto-$stamp"
ee zfs snapshot "$sn"
done
prev=
zfs list -t snapshot -H -o name -S name | grep -E "@auto-[0-9]{12}$" | while read name ; do
dset=${name%@*}
stamp=${name#*auto-}
if [ "$dset" != "$prev" ] ; then
h=$(get_keep "$dset" hourly)
d=$(get_keep "$dset" daily)
w=$(get_keep "$dset" weekly)
prev="$dset"
fi
keep=0
if [ $(date -j $stamp +%w%H%M) = 00000 ] ; then
if [ $w -gt 0 ] ; then
w=$((w - 1))
keep=1
fi
fi
if [ $(date -j $stamp +%H%M) = 0000 ] ; then
if [ $d -gt 0 ] ; then
d=$((d - 1))
keep=1
fi
fi
if [ $h -gt 0 ] ; then
h=$((h - 1))
keep=1
fi
if [ $keep -eq 0 ]; then
ee zfs destroy "$name"
fi
done
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