[linux-lvm] more vg problems or oddities...not using dmsetup remove seems to be bad?
Linda A. Walsh
lvm at tlinx.org
Mon Sep 12 04:08:03 UTC 2011
Here's a sadistic (or masochistic, maybe both, if I do it to myself)...
question...
If I start a snapshot today... (or if one is already running)...
And the merge happens, will the snapshot take today have the
data to undo the merge?
Stuart D. Gathman wrote:
> On Sun, 11 Sep 2011, Stuart D. Gathman wrote:
>
>> On Sun, 11 Sep 2011, Linda A. Walsh wrote:
>>
>>> tried -- merging it...
>>
>> Ooops. You likely did not want that. That reverts the origin volume
>> to the snapshot by copying the original data for updated sectors from
>> the snapshot. This is an extremely useful feature, but *not* when
>> you invoke it accidentally!
>
>>> I'm wondering if I really want this 'merge' it wants to do...and if
>>> not, how do I abort it?
>>
>> If it is really delayed until boot (or close), then you have a chance
>> to abort
>> it, but I don't know how. I hope an expert answers. Meanwhile, I'll
>> peruse the man page to see if it talks about delayed merge.
>
> The man page says:
>
> If both the origin and snapshot volume are not open the merge will
> start
> immediately. Otherwise, the merge will start the first time
> either the
> origin or snap??? shot are activated and both are closed. Merging a
> snapshot
> into an origin that cannot be closed, for example a root
> filesystem, is
> deferred until the next time the origin volume is activated. When
> merging
> starts, the resulting logical volume will have the origin's name, minor
> number and UUID. While the merge is in progress, reads or
> writes to
> the origin appear as they were directed to the snapshot being
> merged. When
> the merge finishes, the merged snapshot is removed. Multiple
> snapshots may
> be specified on the commandline or a @tag may be used to specify
> multi??? ple
> snapshots be merged to their respective origin.
>
> If you have space, I would copy your origin LV while you can. There is
> nothing about cancelling the merge. I suspect you could restore the
> metadata
> backup from before your merge. But make backups first!
>
> --
> Stuart D. Gathman <stuart at bmsi.com>
> Business Management Systems Inc. Phone: 703 591-0911 Fax: 703
> 591-6154
> "Confutatis maledictis, flammis acribus addictis" - background song for
> a Microsoft sponsored "Where do you want to go from here?" commercial.
>
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