Re: [Users] Progress on image operations (dd & USR1 signal)
----- Original Message -----
Hi, I am using ovirt 3.2 and noticed that during image operations
(move,
copy)
the user has no progress report. This is painful, especially if the
images are large
or the storage is slow.
Vdsm uses 'dd' to transfer images and dd provides a simple progress
report, when
it receives the USR1 signal. Could this be uses to provide the user
with
some kind
of progress?
Actually image operations many times occur with qemu-img command so a solution for dd
alone would not suffice, however, this is exactly the reason why we got the qemu folks to
add -USR1 support for qemu-img. So this is in general the plan.
Unfortunately today as you said we do not yet support progress report for these
operations.
If you feel like jumping into the code, we'd be more than happy to help you understand
where changes need to be made (although I'm not sure this specific change would be
trivial).
Right now i would do it with myself with strace and kill, but
ovirt/vdsm
detects an
stderr output and reports a failure.
Actually it only detects a non zero return code, it shouldn't fail on retcode = 0 even
if stderr is nonzero (if you're interested look at execCmd in vdsm/storage/misc.py).
What is the retcode of dd if USR1 is called? if it's none zero then I would say this
is a bug in dd, if it is zero then it sounds like either something else is going on or
that there is a bug in vdsm.
You can see the retcode in the vdsm.log together with the stdout and stderr, can you paste
those after calling -USR1?
$ strace -ff -etrace=write -p `pidof dd` 2>&1 | grep -v 'write(1'
# then, in a second terminal I send the signal
$ killall -USR1 dd
Process 8706 attached - interrupt to quit
--- SIGUSR1 (User defined signal 1) @ 0 (0) ---
write(2, "14022+0 records in\n14021+0 recor"..., 39) = 39
write(2, "14702084096 bytes (15 GB) copied", 32) = 32
write(2, ", 2189.75 s, 6.7 MB/s\n", 22) = 22
--
Ernest Beinrohr, AXON PRO
Ing <http://www.beinrohr.sk/ing.php>;, RHCE
<http://www.beinrohr.sk/rhce.php>;, RHCVA
<http://www.beinrohr.sk/rhce.php>;, LPIC
<http://www.beinrohr.sk/lpic.php>;, +421-2--6241-0360
<callto://+421-2--6241-0360>, +421-903--482-603
<callto://+421-903--482-603>
icq:28153343, skype:oernii-work <callto://oernii-work>,
jabber:oernii@jabber.org
------------------------------------------------------------------------
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bureaucracy.” ― Oscar Wilde
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