Re: [Devil-Linux-discuss] Support for LVM restore from snapshot

[Dominic R. <dl...@ed...>]

On 02/01/2011 23:26, Heiko Zuerker wrote:
> Quoting Dominic Raferd<dl...@ed...>:
>> LVM2 since 2.02.58 supports an option (lvconvert --merge) to merge back
>> an LVM snapshot to an original source. This allows to you create a
>> snapshot, then make 'dangerous' changes to the original source, and
>> afterwards, if unhappy with the changes, simply restore the snapshot to
>> recover the original data.
>>
>> This is potentially very useful but I don't think it will work
>> because the man page [for LVM 2.02.76] says "To check if your kernel
>> supports this feature, look for 'snapshot-merge' in the output of
>> 'dmsetup targets'" And when I do this in DL I don't see snapshot-merge
>> listed.
>>
>> Info about kernel device-mapper snapshot support here:
>> http://alinux.tv/Kernel-2.6.34/device-mapper/snapshot.txt
>> LVM2 changelog here: ftp://sources.redhat.com/pub/lvm2/WHATS_NEW
>>
>> Can I ask for this option (snapshot-merge) to be added to DL kernel for the next mini-release,
>> please (and upgrade LVM to 2.02.79)?
> Unfortunately we froze the Kernel release to 2.6.32.x, since this is
> the long-term stable.
>
> The next major release of DL will have the latest kernel, but we're
> not even anywhere close to an alpha release.
>
> The only way for you to get is, is to create a custom version of DL
> with the latest 2.6 kernel.
I think the more recent 'longterm' kernel is 2.6.35.10, which would have 
the snapshot-merge support. But I will have to be patient...

Dominic