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Re: [Qemu-block] [PATCH v13 00/10] Block replication for continuous chec
From: |
Wen Congyang |
Subject: |
Re: [Qemu-block] [PATCH v13 00/10] Block replication for continuous checkpoints |
Date: |
Fri, 29 Jan 2016 14:52:15 +0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.0 |
On 01/27/2016 07:03 PM, Dr. David Alan Gilbert wrote:
> Hi,
> I've got a block error if I kill the secondary.
>
> Start both primary & secondary
> kill -9 secondary qemu
> x_colo_lost_heartbeat on primary
>
> The guest sees a block error and the ext4 root switches to read-only.
>
> I gdb'd the primary with a breakpoint on quorum_report_bad; see
> backtrace below.
> (This is based on colo-v2.4-periodic-mode of the framework
> code with the block and network proxy merged in; so it could be my
> merging but I don't think so ?)
>
>
> (gdb) where
> #0 quorum_report_bad (node_name=0x7f2946a0892c "node0", ret=-5,
> acb=0x7f2946cb3910, acb=0x7f2946cb3910)
> at /root/colo/jan-2016/qemu/block/quorum.c:222
> #1 0x00007f2943b23058 in quorum_aio_cb (opaque=<optimized out>,
> ret=<optimized out>)
> at /root/colo/jan-2016/qemu/block/quorum.c:315
> #2 0x00007f2943b311be in bdrv_co_complete (acb=0x7f2946cb3f60) at
> /root/colo/jan-2016/qemu/block/io.c:2122
> #3 0x00007f2943ae777d in aio_bh_call (bh=<optimized out>) at
> /root/colo/jan-2016/qemu/async.c:64
> #4 aio_bh_poll (address@hidden) at /root/colo/jan-2016/qemu/async.c:92
> #5 0x00007f2943af5090 in aio_dispatch (ctx=0x7f2945b771d0) at
> /root/colo/jan-2016/qemu/aio-posix.c:305
> #6 0x00007f2943ae756e in aio_ctx_dispatch (source=<optimized out>,
> callback=<optimized out>,
> user_data=<optimized out>) at /root/colo/jan-2016/qemu/async.c:231
> #7 0x00007f293b84a79a in g_main_context_dispatch () from
> /lib64/libglib-2.0.so.0
> #8 0x00007f2943af3a00 in glib_pollfds_poll () at
> /root/colo/jan-2016/qemu/main-loop.c:211
> #9 os_host_main_loop_wait (timeout=<optimized out>) at
> /root/colo/jan-2016/qemu/main-loop.c:256
> #10 main_loop_wait (nonblocking=<optimized out>) at
> /root/colo/jan-2016/qemu/main-loop.c:504
> #11 0x00007f29438529ee in main_loop () at /root/colo/jan-2016/qemu/vl.c:1945
> #12 main (argc=<optimized out>, argv=<optimized out>, envp=<optimized out>)
> at /root/colo/jan-2016/qemu/vl.c:4707
>
> (gdb) p s->num_children
> $1 = 2
> (gdb) p acb->success_count
> $2 = 0
> (gdb) p acb->is_read
> $5 = false
Sorry for the late reply.
What it the value of acb->count?
If secondary host is down, you should remove quorum's children.1. Otherwise,
you will get
I/O error event.
Thanks
Wen Congyang
>
> (qemu) info block
> colo-disk0 (#block080): json:{"children": [{"driver": "raw", "file":
> {"driver": "file", "filename": "/root/colo/bugzilla.raw"}}, {"driver":
> "replication", "mode": "primary", "file": {"port": "8889", "host": "ibpair",
> "driver": "nbd", "export": "colo-disk0"}}], "driver": "quorum", "blkverify":
> false, "rewrite-corrupted": false, "vote-threshold": 1} (quorum)
> Cache mode: writeback, direct
>
> Dave
>
> * Changlong Xie (address@hidden) wrote:
>> Block replication is a very important feature which is used for
>> continuous checkpoints(for example: COLO).
>>
>> You can get the detailed information about block replication from here:
>> http://wiki.qemu.org/Features/BlockReplication
>>
>> Usage:
>> Please refer to docs/block-replication.txt
>>
>> This patch series is based on the following patch series:
>> 1. http://lists.nongnu.org/archive/html/qemu-devel/2015-12/msg04570.html
>>
>> You can get the patch here:
>> https://github.com/Pating/qemu/tree/changlox/block-replication-v13
>>
>> You can get the patch with framework here:
>> https://github.com/Pating/qemu/tree/changlox/colo_framework_v12
>>
>> TODO:
>> 1. Continuous block replication. It will be started after basic functions
>> are accepted.
>>
>> Changs Log:
>> V13:
>> 1. Rebase to the newest codes
>> 2. Remove redundant marcos and semicolon in replication.c
>> 3. Fix typos in block-replication.txt
>> V12:
>> 1. Rebase to the newest codes
>> 2. Use backing reference to replcace 'allow-write-backing-file'
>> V11:
>> 1. Reopen the backing file when starting blcok replication if it is not
>> opened in R/W mode
>> 2. Unblock BLOCK_OP_TYPE_BACKUP_SOURCE and BLOCK_OP_TYPE_BACKUP_TARGET
>> when opening backing file
>> 3. Block the top BDS so there is only one block job for the top BDS and
>> its backing chain.
>> V10:
>> 1. Use blockdev-remove-medium and blockdev-insert-medium to replace backing
>> reference.
>> 2. Address the comments from Eric Blake
>> V9:
>> 1. Update the error messages
>> 2. Rebase to the newest qemu
>> 3. Split child add/delete support. These patches are sent in another
>> patchset.
>> V8:
>> 1. Address Alberto Garcia's comments
>> V7:
>> 1. Implement adding/removing quorum child. Remove the option non-connect.
>> 2. Simplify the backing refrence option according to Stefan Hajnoczi's
>> suggestion
>> V6:
>> 1. Rebase to the newest qemu.
>> V5:
>> 1. Address the comments from Gong Lei
>> 2. Speed the failover up. The secondary vm can take over very quickly even
>> if there are too many I/O requests.
>> V4:
>> 1. Introduce a new driver replication to avoid touch nbd and qcow2.
>> V3:
>> 1: use error_setg() instead of error_set()
>> 2. Add a new block job API
>> 3. Active disk, hidden disk and nbd target uses the same AioContext
>> 4. Add a testcase to test new hbitmap API
>> V2:
>> 1. Redesign the secondary qemu(use image-fleecing)
>> 2. Use Error objects to return error message
>> 3. Address the comments from Max Reitz and Eric Blake
>>
>> Wen Congyang (10):
>> unblock backup operations in backing file
>> Store parent BDS in BdrvChild
>> Backup: clear all bitmap when doing block checkpoint
>> Allow creating backup jobs when opening BDS
>> docs: block replication's description
>> Add new block driver interfaces to control block replication
>> quorum: implement block driver interfaces for block replication
>> Implement new driver for block replication
>> support replication driver in blockdev-add
>> Add a new API to start/stop replication, do checkpoint to all BDSes
>>
>> block.c | 145 ++++++++++++
>> block/Makefile.objs | 3 +-
>> block/backup.c | 14 ++
>> block/quorum.c | 78 +++++++
>> block/replication.c | 545
>> +++++++++++++++++++++++++++++++++++++++++++++
>> blockjob.c | 11 +
>> docs/block-replication.txt | 227 +++++++++++++++++++
>> include/block/block.h | 9 +
>> include/block/block_int.h | 15 ++
>> include/block/blockjob.h | 12 +
>> qapi/block-core.json | 33 ++-
>> 11 files changed, 1089 insertions(+), 3 deletions(-)
>> create mode 100644 block/replication.c
>> create mode 100644 docs/block-replication.txt
>>
>> --
>> 1.9.3
>>
>>
>>
> --
> Dr. David Alan Gilbert / address@hidden / Manchester, UK
>
>
> .
>