[Discuss] lvm snapshot cloning

markw at mohawksoft.com markw at mohawksoft.com
Tue Oct 25 10:16:21 EDT 2011


>> From: discuss-bounces+blu=nedharvey.com at blu.org [mailto:discuss-
>> bounces+blu=nedharvey.com at blu.org] On Behalf Of
>>
>> Other systems, chain snapshots so that at any time, only one snapshot is
>> receiving COW data, and the subsequent snapshots only forward reference.
>
> Also, other systems don't make you pre-allocate disk space for snapshot
> usage, and other systems don't automatically destroy your snapshot if you
> run out of pre-allocated space.  LVM snapshot is crap compared to other
> systems - but if you want to make a single snapshot so you can dump or tar
> your ext3/4 filesystem in a consistent state or something, then it's good
> for that purpose.  And not much else.

As I have said before, that, most of the time, copying the WHOLE volume is
not a practical option.

1TB at a very very fast rate of 160MB/s, copying a 1TB volume takes HOURS!

As for the pre-allocate space issue, yes, that is bad, but using alerts
and monitoring to increase allocated space will prevent the snapshot from
being nuked.

I'm not implying the LVM2 is great, but I do assert it is quite functional.
>
>
>





More information about the Discuss mailing list