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Re: [Qemu-devel] [PATCH V9 00/11] Quorum block driver
From: |
Max Reitz |
Subject: |
Re: [Qemu-devel] [PATCH V9 00/11] Quorum block driver |
Date: |
Tue, 29 Oct 2013 18:55:11 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.0 |
Am 29.10.2013 08:59, schrieb Benoît Canet:
> Le Friday 04 Oct 2013 à 16:31:56 (+0200), Max Reitz a écrit :
>> On 2013-10-02 14:39, Benoît Canet wrote:
>>> It must be applied on top of "block: Add
>>> BlockDriver.bdrv_check_ext_snapshot."
>>>
>>> This patchset create a block driver implementing a quorum using total qemu
>>> disk
>>> images. Writes are mirrored on the $total files.
>>> For the reading part the $total files are read at the same time and a vote
>>> is
>>> done to determine if a qiov version is present $threshold or more times. It
>>> then
>>> return this majority version to the upper layers.
>>> When i < $threshold versions of the data are returned by the lower layer the
>>> quorum is broken and the read return -EIO.
>>>
>>> The goal of this patchset is to be turned in a QEMU block filter living just
>>> above raw-*.c and below qcow2/qed when the required infrastructure will be
>>> done.
>>>
>>> Main use of this feature will be people using NFS appliances which can be
>>> subjected to bitflip errors.
>>>
>>> This patchset can be used to replace blkverify and the out of tree
>>> blkmirror.
>>>
>>> v9: integrate latests comments from kevin
>>>
>>> Benoît Canet (11):
>>> quorum: Create quorum.c, add QuorumSingleAIOCB and QuorumAIOCB.
>>> quorum: Create BDRVQuorumState and BlkDriver and do init.
>>> quorum: Add quorum_aio_writev and its dependencies.
>>> blkverify: Extract qemu_iovec_clone() and qemu_iovec_compare() from
>>> blkverify.
>>> quorum: Add quorum_aio_readv.
>>> quorum: Add quorum mechanism.
>>> quorum: Add quorum_getlength().
>>> quorum: Add quorum_invalidate_cache().
>>> quorum: Add quorum_co_get_block_status.
>>> quorum: Add quorum_co_flush().
>>> quorum: Add quorum_open() and quorum_close().
>>>
>>> block/Makefile.objs | 1 +
>>> block/blkverify.c | 108 +----
>>> block/quorum.c | 1035
>>> +++++++++++++++++++++++++++++++++++++++++++++
>>> configure | 36 ++
>>> include/monitor/monitor.h | 2 +
>>> include/qemu-common.h | 2 +
>>> monitor.c | 2 +
>>> util/iov.c | 103 +++++
>>> 8 files changed, 1183 insertions(+), 106 deletions(-)
>>> create mode 100644 block/quorum.c
>>>
>> Could you add a qemu-iotest if possible?
> I don't see how to specify quorum to qemu-io for bytes checking.
>
> Best regards
>
> Benoît
As of commit b543c5cd, you can pass options to the block driver through
qemu-io -c open. The problem for quorum is that it cannot handle the
filename option (which qemu-io will always set). I've attached a diff to
change this behavior (which makes the path parameter for open optional
and passes NULL to bdrv_open if it is not given). You're free to make
use of it. ;-)
If this diff is applied, you can invoke qemu-io with quorum for example
as following:
qemu-io -c 'open -o
file.driver=quorum,file.children.0.file.filename=[Image
1],file.children.1.file.filename=[Image 2],file.vote_threshold=[x]'
Max
- Re: [Qemu-devel] [PATCH V9 06/11] quorum: Add quorum mechanism., (continued)
[Qemu-devel] [PATCH V9 11/11] quorum: Add quorum_open() and quorum_close()., Benoît Canet, 2013/10/02
Re: [Qemu-devel] [PATCH V9 00/11] Quorum block driver, Max Reitz, 2013/10/04