Block replication is a very important feature which is used for continuous checkpoints(for example: COLO).
Usage: Please refer to docs/block-replication.txt You can get the patch here: https://github.com/wencongyang/qemu-colo/commits/block-replication-v6 The other newest COLO patchse will be sent soon. Note: you should apply the following patch first: http://lists.nongnu.org/archive/html/qemu-devel/2015-05/msg01317.html TODO: 1. Continuous block replication. It will be started after basic functions are accepted. Changs Log: 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 (16): docs: block replication's description allow writing to the backing file Allow creating backup jobs when opening BDS block: Parse "backing_reference" option to reference existing BDS Backup: clear all bitmap when doing block checkpoint Don't allow a disk use backing reference target Add new block driver interface to connect/disconnect the remote target NBD client: implement block driver interfaces to connect/disconnect NBD server Introduce a new -drive option to control whether to connect to remote target NBD client: connect to nbd server later Add new block driver interfaces to control block replication skip nbd_target when starting block replication quorum: implement block driver interfaces for block replication introduce a new API qemu_opts_absorb_qdict_by_index() quorum: allow ignoring child errors Implement new driver for block replication block.c | 279 +++++++++++++++++++++++++++- block/Makefile.objs | 3 +- block/backup.c | 13 ++ block/nbd.c | 69 +++++-- block/quorum.c | 162 ++++++++++++++++- block/replication.c | 441 +++++++++++++++++++++++++++++++++++++++++++++ blockdev.c | 8 + blockjob.c | 10 + docs/block-replication.txt | 179 ++++++++++++++++++ include/block/block.h | 10 + include/block/block_int.h | 18 ++ include/block/blockjob.h | 12 ++ include/qemu/option.h | 2 + qapi/block.json | 16 ++ qemu-options.hx | 4 + tests/qemu-iotests/051 | 13 ++ tests/qemu-iotests/051.out | 13 ++ util/qemu-option.c | 44 +++++ 18 files changed, 1266 insertions(+), 30 deletions(-) create mode 100644 block/replication.c create mode 100644 docs/block-replication.txt -- 2.4.3
