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From: Antoine Martin <antoine@nagafix.co.uk>
To: Michael Tokarev <mjt@tls.msk.ru>
Cc: kvm@vger.kernel.org
Subject: Re: repeatable hang with loop mount and heavy IO in guest
Date: Sat, 27 Feb 2010 00:38:57 +0700	[thread overview]
Message-ID: <4B880731.5090500@nagafix.co.uk> (raw)
In-Reply-To: <4B69CE50.5060901@nagafix.co.uk>


>>   1   0   0  98   0   1|   0     0 |  66B  354B|   0     0 |  30    11
>>   1   1   0  98   0   0|   0     0 |  66B  354B|   0     0 |  29    11
>> From that point onwards, nothing will happen.
>> The host has disk IO to spare... So what is it waiting for??
> Moved to an AMD64 host. No effect.
> Disabled swap before running the test. No effect.
> Moved the guest to a fully up-to-date FC12 server 
> (2.6.31.6-145.fc12.x86_64), no effect.
I have narrowed it down to the guest's filesystem used for backing the 
disk image which is loop mounted: although it was not completely full 
(and had enough inodes), freeing some space on it prevents the system 
from misbehaving.

FYI: the disk image was clean and was fscked before each test. kvm had 
been updated to 0.12.3
The weird thing is that the same filesystem works fine (no system hang) 
if used directly from the host, it is only misbehaving via kvm...

So I am not dismissing the possibility that kvm may be at least partly 
to blame, or that it is exposing a filesystem bug (race?) not normally 
encountered.
(I have backed up the full 32GB virtual disk in case someone suggests 
further investigation)

Cheers
Antoine

  reply	other threads:[~2010-02-26 17:39 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-01-21 17:26 repeatable hang with loop mount and heavy IO in guest Antoine Martin
2010-01-21 20:08 ` RW
2010-01-21 21:08   ` Thomas Beinicke
2010-01-21 21:36     ` RW
2010-01-22  7:57 ` Michael Tokarev
2010-01-22 18:28   ` repeatable hang with loop mount and heavy IO in guest [SOLVED] Antoine Martin
2010-01-22 19:15     ` repeatable hang with loop mount and heavy IO in guest [NOT SOLVED] Antoine Martin
2010-01-24 11:23       ` Antoine Martin
2010-02-03 19:28       ` Antoine Martin
2010-02-26 17:38         ` Antoine Martin [this message]
2010-05-21  9:38           ` repeatable hang with loop mount and heavy IO in guest (now in host - not KVM then..) Antoine Martin
2010-05-22 18:10             ` Jim Paris
2010-05-22 19:33               ` Antoine Martin

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