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From: Stefan Hajnoczi <stefanha@gmail.com>
To: Andy Grover <agrover@redhat.com>
Cc: "Benoît Canet" <benoit.canet@irqsave.net>,
	kwolf@redhat.com, qemu-devel@nongnu.org,
	"Stefan Hajnoczi" <stefanha@redhat.com>,
	pbonzini@redhat.com
Subject: Re: [Qemu-devel] tcmu-runner and QEMU
Date: Thu, 4 Sep 2014 21:16:01 +0100	[thread overview]
Message-ID: <20140904201601.GE25226@stefanha-thinkpad.redhat.com> (raw)
In-Reply-To: <5408821B.4070708@redhat.com>

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On Thu, Sep 04, 2014 at 08:15:39AM -0700, Andy Grover wrote:
> But in the meantime, do you have a use case or user story for the QMP
> support that might help me understand better how it might all fit together?

From my previous email:

"administrator needs to migrate disk images to a new file system or
storage devices without downtime."

Here is some more detail about how that works:

QEMU has a drive-mirror QMP command that copies the disk image to a new
location while continuing to service I/O.  In other words live storage
migration, no downtime.

A tool needs to connect to the QMP unix domain socket and issue the
drive-mirror command.  Then it needs to wait until the QMP events are
raised signalling drive-mirror completion and it block-job-complete QMP
command to atomically switch to the new image file (it is now safe to
delete the old image file).

Stefan

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      parent reply	other threads:[~2014-09-04 20:16 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-29 17:22 [Qemu-devel] tcmu-runner and QEMU Benoît Canet
2014-08-29 18:38 ` Andy Grover
2014-08-29 18:51   ` Benoît Canet
2014-08-29 22:36     ` Andy Grover
2014-08-29 22:46       ` Benoît Canet
2014-08-30 14:46 ` Richard W.M. Jones
2014-08-30 15:53   ` Benoît Canet
2014-08-30 16:02     ` Richard W.M. Jones
2014-08-30 16:04       ` Richard W.M. Jones
2014-08-30 17:22         ` Benoît Canet
2014-08-30 21:50           ` Benoît Canet
2014-08-30 16:51       ` Benoît Canet
2014-08-31 20:03       ` Andy Grover
2014-08-31 20:38         ` Benoît Canet
2014-09-01  8:32           ` Paolo Bonzini
2014-09-01  8:08         ` Paolo Bonzini
2014-09-02  9:25 ` Stefan Hajnoczi
2014-09-03  0:20   ` Andy Grover
2014-09-03  7:34     ` Paolo Bonzini
2014-09-03 13:11     ` Stefan Hajnoczi
2014-09-04 13:24       ` Benoît Canet
2014-09-04 15:15         ` Andy Grover
2014-09-04 15:59           ` Benoît Canet
2014-09-04 20:16           ` Stefan Hajnoczi [this message]

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