Re: Adding snapshot capability to Linux

[Xavier Bestel]

le mar 23-04-2002 à 16:45, Alexander Viro a écrit :
> You _can't_ get consistent snapshots without cooperation from fs.  LVM,
> EVMS, whatever.  Only filesystem knows what IO needs to be pushed to
> make what we have on device consistent and what IO needs to be held
> back.  Neither VFS nor device driver do not and can not have such
> knowledge - it depends both on fs layout and on implementation details.

I always thought that with a journalled fs, data was always consistent
on disk - i.e. always in a state where remounting the image (and
replaying the journal) makes it consistent.