[mythtv-users] MythTV 0.23 Available

[Richard Shaw]

On Tue, May 11, 2010 at 12:34 PM, John Drescher <drescherjm at gmail.com> wrote:
> On Tue, May 11, 2010 at 1:26 PM, Richard Shaw <hobbes1069 at gmail.com> wrote:
>> On Mon, May 10, 2010 at 9:16 PM, Brian J. Murrell <brian at interlinx.bc.ca> wrote:
>>> On Tue, 2010-05-11 at 11:56 +1000, Phill Edwards wrote:
>>>>
>>>> Before I do a major upgrade I use partimage on Sysrecue CD to take a
>>>> partition image copy of my /boot and /root partitions (I don't backup
>>>> the /video partition). So then if anything goes wrong I can restore
>>>> easily (and I have done on quite a few occasions!).
>>>
>>> Yeah.  What he said.  But really, dude, look into LVM and snapshots.
>>> Way easier to manage and do.  No copying and waiting.  Just snapshot and
>>> upgrade.
>>
>> I'm trying to understand how this would work. If we were talking about
>> something like Virtualbox I would understand. The snapshot seems to
>> track changes without modifying the original disk image so if you run
>> into a problem you delete the snapshot and you're back to your
>> pre-upgrade condition.
>>
>> As far as I can tell, LVM snapshots work differently. The underlying
>> file system continues to be modified but it copies the to be modified
>> chucks to the snapshot first to present an unmodified file system.
>>
>> Other than letting you make a live backup (such as dd'ing the who
>> volume) I don't see any real advantage. You still need enough space
>> somewhere to make a complete copy. If you run into an issue, how
>> exactly does this help you?
>>
>
> I believe you only need space for the parts of the filesystem that
> have changed not the entire filesystem.

Sorry, I should have been more explicit. You are correct, but what
does that do for you? LVM snapshots are not persistent. If you don't
do a complete volume backup, what is the snapshot really doing for
you?

Richard