[I apologise for reposting this... but no one replied to my post from Dec, 4th.]
Hallo all,
while experimenting with "zfs send" and "zfs receive" mixed with cloning on
receiver side I found the following...
On server A there is a zpool with snapshots created on regular basis via cron.
Server B get's updated by a zfs-send-ssh-zfs-receive command pipe. Both servers
are running Solaris 10 update 4 (08/07).
Sometimes I want to do some testing on server B without corrupting data on
server A. For doing so I create a clone of the filesystem. Up to here
everything is ok. As long as the mounte clone filesystem is NOT busy, any
further zfs-send-ssh-zfs-receive will work properly, updating my pool on B.
But there are some long running test jobs on server B which keeps clone's
filesystem busy or just a single login shell with its cwd within clone's
filesystem, which makes the filesystem busy from umount's point of view.
Meanwhile another zfs-send-ssh-zfs-receive command gets launched to copy new
snapshot from A to B. If the receiving pool of a zfs-receive-command has busy
clones, the receive command will fail.
For some unknown reason the receive command tries to umount my cloned
filesystem and fails with "Device busy".
The question is: why?
Since the clone is (or should be) independent of its origin, "zfs receive"
should not umount cloned data of older snapshots.
If you want to reproduce this - below (and attached) you find a simple test
script. The script will bump out at last zfs-receive command. If you comment
out the line "cd /mnt/copy", script will run as expected.
Disclaimer: Before running my script, make sure you do not have zpools named
"copy" or "origin". Use this script only on a test machine! Use it at your own
risk.
Here is the script:
<pre>
#!/usr/bin/bash
# cleanup before test
cd /
set -ex
for pool in origin copy; do
zpool destroy $pool || :
rm -f /var/tmp/zpool.$pool
[ -d /mnt/$pool ] && rmdir /mnt/$pool
mkfile -nv 64m /var/tmp/zpool.$pool
zpool create -m none $pool /var/tmp/zpool.$pool
done
zfs create -o mountpoint=/mnt/origin origin/test
update () {
# create/update a log file
date >>/mnt/origin/log
}
snapnum=0
make_snap () {
snapnum=$(($snapnum+1))
zfs snapshot origin/[EMAIL PROTECTED]
}
update
make_snap
update
make_snap
update
make_snap
update
zfs send origin/[EMAIL PROTECTED] | zfs receive -v -d copy
zfs clone copy/[EMAIL PROTECTED] copy/clone
zfs send -i origin/[EMAIL PROTECTED] origin/[EMAIL PROTECTED] | zfs receive -v
-d copy
zfs set mountpoint=/mnt/copy copy/clone
zfs list -r origin copy
cd /mnt/copy # make filesystem busy
zfs send -i origin/[EMAIL PROTECTED] origin/[EMAIL PROTECTED] | zfs receive -v
-d copy
ls -l /mnt/{origin,copy}/log
exit
</pre>
-----
Cleanup with
<pre>
zpool destroy copy; zpool destroy origin; rm /var/tmp/zpool.*
</pre>
after running tests.
- Andreas
This message posted from opensolaris.org
test-zfs-clone.sh
Description: Bourne shell script
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