At 10:20 PM 3/24/00 -0000, jerzy.tomasik@... wrote:

>From: jerzy.tomasik@...
>
>
>I think that you're making an unwarranted assumption that journaling
>is another security layer. I view journaling as a tool for disaster
>recovery. In addition to backup, which is a snapshot in time,
>journaling is an effective way of keeping up to the minute
>incremental backup. This is how we do hot backups with Oracle
>and Informix.
>With Interbase, we run gbak against a live database, and keep the
>database on a RAID 5 device. Still, we've had crashes which
>left us with a corrupted database file and IB was unable to repair
>the database. In our environment (essentially and engineering data
>warehouse) we were able to use the backup and reinsert the raw
>data, however, this wouldn't be acceptable for an OLTP system.
>
>Replication or shadowing don't really solve these problems, even
>if it was true that "disk was cheap." True, if you have a 10GB
>database, it's easy to buy another "Fry's special" and have
>a mirror on another physical device. However, when you approach
>hundreds of GB, suddenly you're up against the number of physical
>slots that you can install on a machine. Less than two years ago
>we bought a HW RAID 5 with 220GB of disk space for about $100K.
>This is not cheap by my standards. Of course, NetApps support
>would help here :-)
>
>I like Jason's idea of the freezepoint. I think it would be an
>elegant solution to my needs. I think it would be really neat
>if it worked closely with journaling file systems (e.g. Veritas).
>What I'd like to see is the ability to create a freezepoint
>and take a consistent snapshot of the file at that time.
>
>

Interbase used to have a journalling subsystem for disaster
recovery that got dropped along the way. The classical
problem with journalling is that tapes fill up. Ironically,
disks are now so big and fast that they almost don't.

The journalling system always started by dumping the current
state of the database (not as bad you might expect) to the
journal, so I suspect the functionality you want is still
sitting around, unloved.

Maybe rekindling the journalling code would make somebody a
nice open source project. Keep you off the streets at night
and all that.

Jim Starkey