Darren J Moffat <[EMAIL PROTECTED]> wrote: > Marcus Sundman wrote: > > Nicolas Williams <[EMAIL PROTECTED]> wrote: > >> On Wed, Feb 27, 2008 at 05:54:29AM +0200, Marcus Sundman wrote: > >>> Nathan Kroenert <[EMAIL PROTECTED]> wrote: > >>>> Are you indicating that the filesystem know's or should know what > >>>> an application is doing?? > >>> Maybe "snapshot file whenever a write-filedescriptor is closed" or > >>> somesuch? > >> Again. Not enough. Some apps (many!) deal with multiple files. > > > > So what? Why would every file-snapshot have to be a file that's > > valid for the application(s) using it? (Certainly zfs snapshots > > don't provide that property either, nor any other backup-related > > system I've seen.) > > If it isn't how does the user or application know that is safe to use > that file ?
Unless the files contain some checksum or somesuch then I guess it doesn't know it's safe. However, that's unavoidable unless the application can use a transaction-supporting fs api. > Is it okay to provide a snapshot of a file that is corrupt and will > cause further more serious data corruption in the application ? Well, apparently so. That's what zfs snapshots do. That's what all backup tools do. Sure it would be better to have full transactions in the fs api, but without that I don't think it's possible to do any better than "the file might be corrupt or it might not, good luck if your file format doesn't support corruption-detection". - Marcus _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
