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> From: Shyh-Wei Luan <[EMAIL PROTECTED]>
> To: Mickey Beddingfield <[EMAIL PROTECTED]>; [EMAIL PROTECTED]
> Subject: Re: last volume access time / volume space management
> Date: Wednesday, October 30, 1996 6:07 PM
>
> On Oct 30, 5:23am, Mickey Beddingfield wrote:
>
> >
> > In our case we plan to use a near line storage device that will allow
> > access to the volume at a reasonable rate??? Anyway, the Load Bal.
scripts
> > will detect a use of the volume & it will be moved back to real disk
the
> > night after an access.
>
> I am interested in how the Load Bal would detect a use of a volume that
had
> be migrated to tape. I was thinking this must be triggered by vldb not
being
> able to locate a migrated volume. Once this can be detected, the
"reloading"
> of the volume should happen right away, why wait till the night?
>
Sorry, but there seems to be a disconnect here? I have been talking about
moving volumes to a nearline storage device that looks like a disk or
disks. Some of these devices use optical media and some use tape & staging
disks. If you use a device like this then this partition or partitions can
be mounted under AFS & thus you have a bigger cell so all the info is still
in the VLDB, etc. We are looking at a device like this now and expect our
cost/MB to be ~$.20/MB vs real disk at ~$.45/MB vs RAID at ~$.75/MB
> >
> > If a volume is dectected to be "not used" it must have been so for a
period
> > of time that will allow us to go through at least one full backup
cycle.
> > Once its moved to nearline storage then we don't really need to keep
> > backing up the volume? I don't think??? Or I can't see any reason why
we
> > would need to do so. Anyway, the next time it is "used" it will be
> > scheduled for a move & thus be back on the backup list. We should
always
> > have a good backup copy of this volume on tape even if we have a
problem
> > with the near line storage device.
>
> If a volume stay migrated for a long time, the backup done before the
migration
> might get expired and overwritten. This is especially true if you are
using
> the AFS backup system (backup, butc, buserver) and tape recycling, right?
We build backup lists every night to determine what volumes need to be
backed up full or incremental. We can specify what servers/partitions will
be backed up, thus we can elect not to backup this nearline storage devices
partition or partitions. Also, we keep our weekly full backups for three
years so unless our users need something for more than 3 years we are
covered. We also allow special backups to be requested by our users such
that they can be kept for a longer period of time? Lastly, if the backup
is scratched after three years, all the user will need to do is use the
volume so that it is brought back to real disk/RAID, and thus a backup will
be made again...
>
> Shyh-Wei
>
