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

Lars Ellenberg Lars.Ellenberg at linbit.com
Thu Apr 8 00:44:37 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.

/ 2004-04-08 00:24:01 +0200
\ Lars Marowsky-Bree:
> 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 yes, they'll restore a clean snapshot in >95% of the cases, and is
> why drbd is so stringent about write ordering ;-)

I distinguish between
"consistent" as in "useable by replaying/undoing some transactions based on logs"
and "clean" as in "no pending transactions".

	Lars Ellenberg

More information about the drbd-user mailing list