[DRBD-user] DRBD and LVM Snapshot with 2 nodes configuration

Andreas Semt as at computer-leipzig.de
Thu Apr 8 00:46:56 CEST 2004

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

Lars Marowsky-Bree wrote:

> On 2004-04-07T23:54:25,
>    Lars Ellenberg <Lars.Ellenberg at linbit.com> said:
>> consistent and clean from the file system point of view.
>> The applications runnig on top of it (SQL databases and so on)
>> Probably have even more problems to provide not only some
>> consistent, but a *clean* view of their data...
> If the application does not have a consistent snapshot on disk at all
> times, it's not a database. No current database gets that wrong, the
> journaling et al are they key feature, and it would be beyond
> tremendously broken. If the application database designer is not using
> transactions correctly in the application, he ought to be taken out and
> shot.

So the best way would be a LVM2 snapshot with LVM2 on top of drbd (and 
fs on top of LVM2). Anybody with some experiences for LVM2 on top of 
drbd? Perhaps some advices for the filter (for doing a snapshot and 
therefore hiding the lower level devices from lvm2), too? ;-)
> So yes, they'll restore a clean snapshot in >95% of the cases, and is
> why drbd is so stringent about write ordering ;-)

Good to know.
> Sincerely,
>     Lars Marowsky-Brée <lmb at suse.de>

Best regards,
Andreas Semt

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