Re: [linux-lvm] how to copy a snapshot, or restore snapshot without deleting it

From: "Tomas Dalebjörk" <tomas.dalebjork@gmail.com>
To: LVM general discussion and development <linux-lvm@redhat.com>
Subject: Re: [linux-lvm] how to copy a snapshot, or restore snapshot without deleting it
Date: Thu, 3 Jan 2019 10:32:33 +0100	[thread overview]
Message-ID: <CACrcyfKe7X2XAGUqDsksbNqgRtf4F7oCvUcdQ1A3S67L48Z1ng@mail.gmail.com> (raw)
In-Reply-To: <MEAPR01MB502904BB1C62BCAEDA77544FC28D0@MEAPR01MB5029.ausprd01.prod.outlook.com>

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Hi,

Drop me an email; there are other ways to perform this without "destroying"
the old snapshot.

Regards Tomas

Den tors 3 jan. 2019 kl 10:29 skrev Davis, Matthew <
Matthew.Davis.2@team.telstra.com>:

> Hi,
>
> I want to restore a snapshot without deleting the snapshot.
>
> My use case is that I'm experimenting with a lot of different drivers,
> kernel modules, and file modifications all over my machine.
> I want to
> 1. take a snapshot of the working system
> 2. make changes
> 3. restore the snapshot (` sudo lvconvert --merge
> /dev/ubuntu-vg/$SNAPSHOT` then reboot)
> 4. make new changes
> 5. restore to the snapshot again
>
> The problem is that step 3 deletes the snapshot, so step 5 fails.
>
> My current workaround is:
> 1. take a snapshot of the working system
> 2. make changes
> 3. restore the snapshot (` sudo lvconvert --merge
> /dev/ubuntu-vg/$SNAPSHOT` then reboot)
> 4. Wait 1.5 hours, without making any changes to the machine
> 5. Take a new snapshot, with the same name as the original
> 6. make new changes
> 7. restore to the snapshot
>
> This is not great because:
> * I sometimes forget to do step 5
> * I can't take a snapshot of the volume while it is still merging. This
> takes 1.5 hours. I want to be able to restore my snapshots multiple times
> per day
>
>
> Is there a flag I can add to `lvconvert` to make it not delete the
> snapshot?
> Alternatively, is there a way I can make a copy of the snapshot before I
> restore it?
>
> It looks like someone else asked this question 10 years ago.
> https://www.redhat.com/archives/linux-lvm/2008-November/msg00000.html
> Has this problem been solved since then?
>
> Thanks,
> Matt Davis
>
> Technical Specialist
> Telstra | Product Strategy & Innovation - Telstra Labs | Programmable
> Infrastructure
> E  Matthew.Davis.2@team.telstra.com
>
>
>
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> linux-lvm@redhat.com
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> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>

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