From: Fam Zheng <famz@redhat.com>
To: Wen Congyang <wency@cn.fujitsu.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
Lai Jiangshan <laijs@cn.fujitsu.com>,
Jiang Yunhong <yunhong.jiang@intel.com>,
Dong Eddie <eddie.dong@intel.com>,
qemu devel <qemu-devel@nongnu.org>,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
Gonglei <arei.gonglei@huawei.com>,
Stefan Hajnoczi <stefanha@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Yang Hongyang <yanghy@cn.fujitsu.com>,
zhanghailiang <zhang.zhanghailiang@huawei.com>
Subject: Re: [Qemu-devel] [RFC PATCH 01/14] docs: block replication's description
Date: Thu, 12 Feb 2015 15:21:17 +0800 [thread overview]
Message-ID: <20150212072117.GB32554@ad.nay.redhat.com> (raw)
In-Reply-To: <1423710438-14377-2-git-send-email-wency@cn.fujitsu.com>
Hi Congyang,
On Thu, 02/12 11:07, Wen Congyang wrote:
> +== Workflow ==
> +The following is the image of block replication workflow:
> +
> + +----------------------+ +------------------------+
> + |Primary Write Requests| |Secondary Write Requests|
> + +----------------------+ +------------------------+
> + | |
> + | (4)
> + | V
> + | /-------------\
> + | Copy and Forward | |
> + |---------(1)----------+ | Disk Buffer |
> + | | | |
> + | (3) \-------------/
> + | speculative ^
> + | write through (2)
> + | | |
> + V V |
> + +--------------+ +----------------+
> + | Primary Disk | | Secondary Disk |
> + +--------------+ +----------------+
> +
> + 1) Primary write requests will be copied and forwarded to Secondary
> + QEMU.
> + 2) Before Primary write requests are written to Secondary disk, the
> + original sector content will be read from Secondary disk and
> + buffered in the Disk buffer, but it will not overwrite the existing
> + sector content in the Disk buffer.
I'm a little confused by the tenses ("will be" versus "are") and terms. I am
reading them as "s/will be/are/g"
Why do you need this buffer?
If both primary and secondary write to the same sector, what is saved in the
buffer?
Fam
> + 3) Primary write requests will be written to Secondary disk.
> + 4) Secondary write requests will be buffered in the Disk buffer and it
> + will overwrite the existing sector content in the buffer.
> +
next prev parent reply other threads:[~2015-02-12 7:21 UTC|newest]
Thread overview: 81+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-12 3:07 [Qemu-devel] [RFC PATCH 00/14] Block replication for continuous checkpoints Wen Congyang
2015-02-12 3:07 ` [Qemu-devel] [RFC PATCH 01/14] docs: block replication's description Wen Congyang
2015-02-12 7:21 ` Fam Zheng [this message]
2015-02-12 7:40 ` Wen Congyang
2015-02-12 8:44 ` Fam Zheng
2015-02-12 9:33 ` Wen Congyang
2015-02-12 9:44 ` Fam Zheng
2015-02-12 10:11 ` Wen Congyang
2015-02-12 10:26 ` famz
2015-02-13 5:09 ` Wen Congyang
2015-02-13 7:01 ` Fam Zheng
2015-02-13 20:29 ` John Snow
2015-03-03 7:53 ` Wen Congyang
2015-03-03 7:59 ` Fam Zheng
2015-03-03 12:12 ` Wen Congyang
2015-03-11 6:44 ` Wen Congyang
2015-03-11 6:49 ` Fam Zheng
2015-03-11 7:01 ` Wen Congyang
2015-03-11 7:04 ` Fam Zheng
2015-03-11 7:12 ` Wen Congyang
2015-03-13 9:01 ` Wen Congyang
2015-03-13 9:05 ` Fam Zheng
2015-03-16 6:19 ` Wen Congyang
2015-03-25 12:41 ` Paolo Bonzini
2015-02-12 9:36 ` Hongyang Yang
2015-02-12 9:46 ` Fam Zheng
2015-02-24 7:50 ` Wen Congyang
2015-02-25 2:46 ` Fam Zheng
2015-02-25 8:36 ` Wen Congyang
2015-02-25 8:58 ` Fam Zheng
2015-02-25 9:58 ` Wen Congyang
2015-02-26 6:38 ` Wen Congyang
2015-02-26 8:44 ` Fam Zheng
2015-02-26 9:07 ` Wen Congyang
2015-02-26 10:02 ` Fam Zheng
2015-02-27 2:27 ` Wen Congyang
2015-02-27 2:32 ` Fam Zheng
2015-02-25 8:11 ` Wen Congyang
2015-02-25 8:18 ` Fam Zheng
2015-02-25 9:10 ` Wen Congyang
2015-02-25 9:45 ` Fam Zheng
2015-03-04 16:35 ` Dr. David Alan Gilbert
2015-03-05 1:03 ` Wen Congyang
2015-03-05 19:04 ` Dr. David Alan Gilbert
2015-02-12 3:07 ` [Qemu-devel] [RFC PATCH 02/14] quorom: add a new read pattern Wen Congyang
2015-02-12 6:42 ` Gonglei
2015-02-23 20:36 ` Max Reitz
2015-02-23 21:56 ` Eric Blake
2015-02-12 3:07 ` [Qemu-devel] [RFC PATCH 03/14] quorum: ignore 0-length child Wen Congyang
2015-02-23 20:43 ` Max Reitz
2015-02-24 2:33 ` Wen Congyang
2015-03-18 5:29 ` Wen Congyang
2015-03-18 12:57 ` Max Reitz
2015-02-12 3:07 ` [Qemu-devel] [RFC PATCH 04/14] Add new block driver interfaces to control disk replication Wen Congyang
2015-02-23 20:57 ` Max Reitz
2015-02-23 21:58 ` Eric Blake
2015-02-12 3:07 ` [Qemu-devel] [RFC PATCH 05/14] quorom: implement block driver interfaces for block replication Wen Congyang
2015-02-23 21:22 ` Max Reitz
2015-02-12 3:07 ` [Qemu-devel] [RFC PATCH 06/14] NBD client: connect to nbd server later Wen Congyang
2015-02-23 21:31 ` Max Reitz
2015-02-25 2:23 ` Wen Congyang
2015-02-25 14:22 ` Max Reitz
2015-02-26 14:07 ` Paolo Bonzini
2015-02-12 3:07 ` [Qemu-devel] [RFC PATCH 07/14] NBD client: implement block driver interfaces for block replication Wen Congyang
2015-02-23 21:41 ` Max Reitz
2015-02-26 14:08 ` Paolo Bonzini
2015-02-12 3:07 ` [Qemu-devel] [RFC PATCH 08/14] block: add a new API to create a hidden BlockBackend Wen Congyang
2015-02-23 21:48 ` Max Reitz
2015-02-12 3:07 ` [Qemu-devel] [RFC PATCH 09/14] block: give backing image its own BlockBackend Wen Congyang
2015-02-23 21:53 ` Max Reitz
2015-02-12 3:07 ` [Qemu-devel] [RFC PATCH 10/14] allow the backing image access the origin BlockDriverState Wen Congyang
2015-02-23 22:01 ` Max Reitz
2015-02-12 3:07 ` [Qemu-devel] [RFC PATCH 11/14] allow writing to the backing file Wen Congyang
2015-02-23 22:03 ` Max Reitz
2015-02-26 14:15 ` Paolo Bonzini
2015-02-12 3:07 ` [Qemu-devel] [RFC PATCH 12/14] Add disk buffer for block replication Wen Congyang
2015-02-23 22:27 ` Max Reitz
2015-02-12 3:07 ` [Qemu-devel] [RFC PATCH 13/14] COW: move cow interfaces to a seperate file Wen Congyang
2015-02-12 3:07 ` [Qemu-devel] [RFC PATCH 14/14] COLO: implement a new block driver Wen Congyang
2015-02-23 22:35 ` Max Reitz
2015-02-18 16:26 ` [Qemu-devel] [RFC PATCH 00/14] Block replication for continuous checkpoints Paolo Bonzini
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