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From: Wen Congyang <wency@cn.fujitsu.com>
To: Stefan Hajnoczi <stefanha@redhat.com>,
	Changlong Xie <xiecl.fnst@cn.fujitsu.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Fam Zheng <famz@redhat.com>,
	zhanghailiang <zhang.zhanghailiang@huawei.com>,
	fnstml-hwcolo@cn.fujitsu.com, qemu devel <qemu-devel@nongnu.org>,
	Max Reitz <mreitz@redhat.com>, Gonglei <arei.gonglei@huawei.com>,
	Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [Qemu-devel] [PATCH v14 7/8] Implement new driver for block replication
Date: Mon, 1 Feb 2016 09:13:36 +0800	[thread overview]
Message-ID: <56AEB140.3060509@cn.fujitsu.com> (raw)
In-Reply-To: <20160129154648.GE11427@stefanha-x1.localdomain>

On 01/29/2016 11:46 PM, Stefan Hajnoczi wrote:
> On Fri, Jan 29, 2016 at 11:13:42AM +0800, Changlong Xie wrote:
>> On 01/28/2016 11:15 PM, Stefan Hajnoczi wrote:
>>> On Thu, Jan 28, 2016 at 09:13:24AM +0800, Wen Congyang wrote:
>>>> On 01/27/2016 10:46 PM, Stefan Hajnoczi wrote:
>>>>> On Wed, Jan 13, 2016 at 05:18:31PM +0800, Changlong Xie wrote:
>>> I'm concerned that the bdrv_drain_all() in vm_stop() can take a long
>>> time if the disk is slow/failing.  bdrv_drain_all() blocks until all
>>> in-flight I/O requests have completed.  What does the Primary do if the
>>> Secondary becomes unresponsive?
>>
>> Actually, we knew this problem. But currently, there seems no better way to
>> resolve it. If you have any ideas?
> 
> Is it possible to hold the checkpoint information and acknowledge the
> checkpoint right away, without waiting for bdrv_drain_all() or any
> Secondory guest activity to complete?

There is no way to know that secondary becomes unreponsive.

> 
> I think this really means falling back to microcheckpointing until the
> Secondary guest can checkpoint.  Instead of a blocking vm_stop() we
> would prevent vcpus from running and when the last pending I/O finishes
> the Secondary could apply the last checkpoint.  This approach does not
> block QEMU (the monitor, etc).
> 

If secondary host becomes unresponsive, it means that we cannot do mocrocheckpointing.
We should do failover in this case.

Thanks
Wen Congyang

  reply	other threads:[~2016-02-01  1:13 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-13  9:18 [Qemu-devel] [PATCH v14 0/8] Block replication for continuous checkpoints Changlong Xie
2016-01-13  9:18 ` [Qemu-devel] [PATCH v14 1/8] unblock backup operations in backing file Changlong Xie
2016-01-13  9:18 ` [Qemu-devel] [PATCH v14 2/8] Store parent BDS in BdrvChild Changlong Xie
2016-01-13  9:18 ` [Qemu-devel] [PATCH v14 3/8] Backup: clear all bitmap when doing block checkpoint Changlong Xie
2016-01-27 16:05   ` Stefan Hajnoczi
2016-01-28  2:22     ` Changlong Xie
2016-01-13  9:18 ` [Qemu-devel] [PATCH v14 4/8] Allow creating backup jobs when opening BDS Changlong Xie
2016-01-27 14:04   ` Stefan Hajnoczi
2016-01-28  2:22     ` Changlong Xie
2016-01-13  9:18 ` [Qemu-devel] [PATCH v14 5/8] docs: block replication's description Changlong Xie
2016-02-02 15:20   ` Eric Blake
2016-02-03  3:18     ` Changlong Xie
2016-02-03  3:35       ` Eric Blake
2016-02-03  3:40         ` Wen Congyang
2016-01-13  9:18 ` [Qemu-devel] [PATCH v14 6/8] auto complete active commit Changlong Xie
2016-01-13  9:18 ` [Qemu-devel] [PATCH v14 7/8] Implement new driver for block replication Changlong Xie
2016-01-20  0:04   ` Eric Blake
2016-01-20  7:45     ` Changlong Xie
2016-01-27 14:46   ` Stefan Hajnoczi
2016-01-28  1:13     ` Wen Congyang
2016-01-28 15:15       ` Stefan Hajnoczi
2016-01-29  3:13         ` Changlong Xie
2016-01-29 15:46           ` Stefan Hajnoczi
2016-02-01  1:13             ` Wen Congyang [this message]
2016-02-02 14:34               ` Stefan Hajnoczi
2016-02-03  1:29                 ` Wen Congyang
2016-02-03  9:32                   ` Stefan Hajnoczi
2016-02-03  9:55                     ` Wen Congyang
2016-02-03 11:25                       ` Hailiang Zhang
2016-01-13  9:18 ` [Qemu-devel] [PATCH v14 8/8] support replication driver in blockdev-add Changlong Xie
2016-01-14  1:12 ` [Qemu-devel] [PATCH v14 0/8] Block replication for continuous checkpoints Changlong Xie
2016-01-19  1:27   ` Hailiang Zhang
2016-01-24 13:34 ` Wen Congyang
2016-01-26 16:04   ` Stefan Hajnoczi

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