From: Paolo Bonzini <pbonzini@redhat.com>
To: Alex Bligh <alex@alex.org.uk>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] When does live migration give up?
Date: Wed, 04 Sep 2013 19:07:53 +0200 [thread overview]
Message-ID: <522768E9.9080408@redhat.com> (raw)
In-Reply-To: <A35D54FFEC699EB4F69642B7@nimrod.local>
Il 04/09/2013 17:24, Alex Bligh ha scritto:
> We have seen a situation when migrating about 50 VMs at once where some
> of them fail. I think this is because they are dirtying pages faster than
> they can be transmitted.
No, migration never "gives up". It may never converge, but it keeps
trying until cancelled.
Could it be that you are choosing migration server ports from a small
range, and some of them are failing because two migrations pick the same
random port for the destination (which is where the server socket lies)?
Paolo
> What algorithm controls when migration fails in this way, and is it
> tunable?
>
> I am fully aware one answer to this question is "do not attempt to
> migrate 50 busy VMs through a single 1GB/s NIC".
next prev parent reply other threads:[~2013-09-04 17:08 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-04 15:24 [Qemu-devel] When does live migration give up? Alex Bligh
2013-09-04 17:07 ` Paolo Bonzini [this message]
2013-09-04 18:05 ` Alex Bligh
2013-09-04 18:34 ` Paolo Bonzini
2013-09-04 22:37 ` Alex Bligh
2013-09-04 18:35 ` Alex Bligh
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