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From: Zdenek Kabelac <zkabelac@redhat.com>
Message-ID: <935364b3-a535-fddc-bf6c-120b46719e2f@redhat.com>
Date: Mon, 28 Jan 2019 12:49:31 +0100
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Subject: Re: [linux-lvm] how to copy a snapshot,
	or restore snapshot without deleting it
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To: LVM general discussion and development <linux-lvm@redhat.com>, Zdenek Kabelac <zkabelac@redhat.com>, "Davis, Matthew" <Matthew.Davis.2@team.telstra.com>

Dne 21. 01. 19 v 11:32 Zdenek Kabelac napsal(a):
> Dne 18. 01. 19 v 1:53 Davis, Matthew napsal(a):
>> Hi Zdenek,
>>
>> I assumed that LVM thin snapshots would work like git branches.
>> Since git also uses diffs on the backend, and git is popular with=20
>> developers, the same kind of behaviour seems reasonable to me.
>>
>=20
> Hi
>=20
> There is very good reason why the git is not really a good tool for stori=
ng=20
> binary data...
>=20
> Your use-case is 'very specific' sub-case of many different usability=20
> scenarios you can do with lvm2 -=EF=BF=BD so while you might see some pot=
ential=20
> benefit if the lvm2 would work more closely to git logic,
> it would look terrible in many other situations.
>=20

Hi

Adding some more thoughts here - we can probably give user an option to=20
control this - particularly in this case  - how about something like:

lvconvert --mergesnapshot --keeporigin y|n

so if user would specify 'y' - lvm2 would relink/preserve merged snapshot a=
s=20
an origin for all other existing snapshots of the old origin - this would m=
ake=20
more obvious what is going to happen when you start creating and merging lo=
ts=20
of them into a single origin.

(yeah - maybe there could be better fitting option name - so it's more about
idea here for now)

Zdenek