- Liran Avi Kivity <a...@redhat.com> wrote on 02/11/2009 20:47:34: > On 11/02/2009 03:40 PM, lir...@il.ibm.com wrote: > > This series adds support for live migration without shared storage, means > > copy the storage while migrating. It was tested with KVM. Supports 2 ways > > to replicate the storage during migration: > > 1. Complete copy of storage to destination > > 2. Assuming the storage is cow based, copy only the allocated > > data, time of the migration will be linear with the amount of allocated > > data (user responsibility to verify that the same backend file reside > > on src and destination). > > > > Live migration will work as follows: > > (qemu) migrate -d tcp:0:4444 # for ordinary live migration > > (qemu) migrate -d blk tcp:0:4444 # for live migration with > complete storage copy > > (qemu) migrate -d blk inc tcp:0:4444 # for live migration with > incremental storage copy, storage is cow based. > > > > I'd like to see the syntax generalized. For one, the guest may have > several disks; an install image cdrom might be available as an nfs image > but the main storage is local. Secondly, there can be several levels of > cow and we want to control which one we copy. > > I'll leave the exact details to the qpeople, but if we can specify a > copy depth for each device, where 0=copy nothing, n=copy everything, > 1=copy the last level (equivalent to -d blk inc) I think we'll have > covered everything.
I propose the following syntax: migrate [-d] [-b [<device:copy_level> ...<device:copy_level>]] tcp:<host>:<port> Where device will be the name of the device: ide0-hd0. And copy_level will be integer or n, 0=flat copy of the device, 1=copy the last level ... n=copy all levels. All HD devices that will not appear in the command will be treated as copy_level=0. All devices != BDRV_TYPE_HD will be ignored. What do you think? - Liran
