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Re: [Qemu-block] [PATCH v10 10/16] docs: Document how to stream to an in
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-block] [PATCH v10 10/16] docs: Document how to stream to an intermediate layer |
Date: |
Wed, 12 Oct 2016 16:39:09 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
Am 06.10.2016 um 15:02 hat Alberto Garcia geschrieben:
> Signed-off-by: Alberto Garcia <address@hidden>
> ---
> docs/live-block-ops.txt | 31 ++++++++++++++++++++-----------
> 1 file changed, 20 insertions(+), 11 deletions(-)
>
> diff --git a/docs/live-block-ops.txt b/docs/live-block-ops.txt
> index a257087..014c8c9 100644
> --- a/docs/live-block-ops.txt
> +++ b/docs/live-block-ops.txt
> @@ -10,9 +10,9 @@ Snapshot live merge
> Given a snapshot chain, described in this document in the following
> format:
>
> -[A] -> [B] -> [C] -> [D]
> +[A] <- [B] <- [C] <- [D] <- [E]
>
> -Where the rightmost object ([D] in the example) described is the current
> +Where the rightmost object ([E] in the example) described is the current
> image which the guest OS has write access to. To the left of it is its base
> image, and so on accordingly until the leftmost image, which has no
> base.
> @@ -21,11 +21,14 @@ The snapshot live merge operation transforms such a chain
> into a
> smaller one with fewer elements, such as this transformation relative
> to the first example:
>
> -[A] -> [D]
> +[A] <- [E]
>
> -Currently only forward merge with target being the active image is
> -supported, that is, data copy is performed in the right direction with
> -destination being the rightmost image.
> +Data is copied in the right direction with destination being the
> +rightmost image, but any other intermediate image can be specified
> +instead. In this example data is copied from [C] into [D], so [D] can
> +be backed by [B]:
> +
> +[A] <- [B] <- [D] <- [E]
>
> The operation is implemented in QEMU through image streaming facilities.
This whole document is hopelessly outdated. At least, we need to clarify
here that streaming isn't the only operation that exists and that the
explanation refers to streaming only.
Ideally we would also add a section on commit. And likeweise, the next
section about "live block copy" should be extended to cover mirror and
backup.
Kevin
- [Qemu-block] [PATCH v10 08/16] block: Support streaming to an intermediate layer, (continued)
- [Qemu-block] [PATCH v10 04/16] block: Use block_job_add_bdrv() in backup_start(), Alberto Garcia, 2016/10/06
- [Qemu-block] [PATCH v10 05/16] block: Check blockers in all nodes involved in a block-commit job, Alberto Garcia, 2016/10/06
- [Qemu-block] [PATCH v10 10/16] docs: Document how to stream to an intermediate layer, Alberto Garcia, 2016/10/06
- Re: [Qemu-block] [PATCH v10 10/16] docs: Document how to stream to an intermediate layer,
Kevin Wolf <=
- [Qemu-block] [PATCH v10 14/16] qemu-iotests: Test block-stream and block-commit in parallel, Alberto Garcia, 2016/10/06
- [Qemu-block] [PATCH v10 16/16] qemu-iotests: Test streaming to a Quorum child, Alberto Garcia, 2016/10/06
- [Qemu-block] [PATCH v10 13/16] qemu-iotests: Test overlapping stream and commit operations, Alberto Garcia, 2016/10/06
- [Qemu-block] [PATCH v10 01/16] block: Pause all jobs during bdrv_reopen_multiple(), Alberto Garcia, 2016/10/06
[Qemu-block] [PATCH v10 07/16] block: Block all intermediate nodes in commit_active_start(), Alberto Garcia, 2016/10/06