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From: Alexandre DERUMIER <aderumier@odiso.com>
To: qemu-devel <qemu-devel@nongnu.org>
Subject: [Qemu-devel] qmp block-mirror hang, lots of nfs op/s on nfs source disk
Date: Mon, 11 May 2015 13:38:23 +0200 (CEST)	[thread overview]
Message-ID: <1050461611.181154015.1431344303354.JavaMail.zimbra@oxygem.tv> (raw)

Hi,

I'm currently playing with drive-mirror, (qemu 2.2)

and I have qmp hang when drive-mirror is starting.

just after qmp "drive-mirror" exec, qmp socket or hmp are not responding.

After some times it's working again, and I can see result of query-block-jobs.


The source volume is on nfs (v4), and it seem that the bigger the volume is, the bigger I need to wait before the mirror begin.


Looking at nfsiostat

   op/s		rpc bklog
1806.00 	   0.00
read:             ops/s		   kB/s		  kB/op		retrans		avg RTT (ms)	avg exe (ms)
		  0.000 	  0.000 	  0.000        0 (0.0%) 	  0.000 	  0.000
write:            ops/s		   kB/s		  kB/op		retrans		avg RTT (ms)	avg exe (ms)
		  0.000 	  0.000 	  0.000        0 (0.0%) 	  0.000 	  0.000


I'm seeing a lot of  nfs op/s on source disk (but not read).

I wonder if some kind of source file scan is done ? is it expected ?

I can reproduce it 100%

I found a report on redhat bugzilla here, which seem to have same behaviour (not on nfs):
https://bugzilla.redhat.com/show_bug.cgi?id=1185172

             reply	other threads:[~2015-05-11 11:38 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-11 11:38 Alexandre DERUMIER [this message]
2015-05-11 11:46 ` [Qemu-devel] qmp block-mirror hang, lots of nfs op/s on nfs source disk Paolo Bonzini
2015-05-11 12:03   ` Alexandre DERUMIER

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