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Re: [Qemu-devel] [PATCH v2 0/6] external backup api
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH v2 0/6] external backup api |
Date: |
Thu, 10 Mar 2016 18:40:27 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 |
On 10/03/2016 18:37, Stefan Hajnoczi wrote:
> I suggest giving the new NBD command a "type" argument:
> 0 - SCSI mapped/anchored values according to SCSI Get LBA Status
> 1 - Dirty/clean, useful for incremental backup and other blocking tracking
> cases
>
> This way we don't impinge on SCSI semantics and the command can be
> used for both traditional logical block provisioning and dirty bitmap
> info.
>
> When the NBD export is started in QEMU you can optionally associate it
> with a bitmap. This bitmap is used to provide type=1 (dirty/clean)
> status information.
Good idea. The precedent in NBD is to use bits 16..31 of the command
for flags, so it could go there.
Paolo