Hung processes during copy operations

Ulrich Petri u.petri at
Mon May 23 07:45:45 EDT 2011

One thing I forgot to add:
After the last reboot I had to zpool import -f the pool in order to
get it back as zpool claimed the pool was from a foreign system.

On May 23, 1:33 pm, Ulrich Petri < at> wrote:
> Hi Brian,
> On May 16, 11:26 pm, Brian Behlendorf <behlendo... at> wrote:
> > Have you tried the latest source from the zfs master branch?  I recently
> > committed a fix which might address this issue.  It's hard to be certain
> > from the stacks included in your email, but it's certainly possible.
> > Commit 21ade34 fixed issues #232 which was very similar to the problem
> > your describing.
> I updated spl to 372c2572336 and zfs to d9bfe0f57 and at first it
> seemed that this solved the problems. There were still some long
> periods of rsync being in state D but it came out of it eventually.
> Unfortunately this weekend the system hung again.
> This time I had a script running that logged the memory usage every 10
> seconds (I thought maybe that was a clue to what is going on) and the
> memory usage definitely looks unusual to me.
> You can see the graph here [1] (takes a while to load).
> There is nothing running on this machine besides ZFS, rsync copying
> data over and the usual system deamons present on a freshly installed
> ubuntu system.
> When the system was in the hung state everything that tries to
> interact with the zfs volumes (e.g zpool / zfs commands and updatedb)
> also hung.
> Here is the complete dmesg output [2]. The hung reporting eventually
> stopps because it reached the maximum hung reporing number.
> Also look at the output of "ps fax" [3] shortly before I rebooted the
> machine. Notice that the txg_sync process is also in state D
> I just saw another thread on the list [4] that seems to describe the
> same (or at least very similar) problem. In both cases many small
> files seem to be involved.
> Bye
> Ulrich
> [1]
> [2]
> [3]
> [4]

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