As with most things, it all depends on what you want to accomplish. You could get by without any holding disk, forcing all your backups to go directly to tape, but this would take longer since whenever the tape drive caught up with the data stream it would have to stop and reposition itself. Any tape error would cause the backups to not be done. Also, you need a much longer backup window since the backups would have to be don serially. With a holding disk as large as one or two of your largest partitions, Amanda can spool the backup images to the holding disk, and when an image is complete Amanda can flush it to tape in one continuous stream while collecting other images on the holding disk. This speeds up your backups and shortens your required backup window. If a tape error occurs then whatever complete images that will fit on the holding disk will continue and can be flushed to tape later. With a holding disk as large as your complete backup, you will still get a complete backup run even if you forget to put a tape in the drive. This also helps if there is a tape error early in the run and on holidays. You can also increase the number of dumpers running in parallel to shorten your backup window. There are also people on the list with large tapes and small daily runs that let backups accumulate on the holding disk until they have a tape's worth, and then flush the collected backups to tape. There have been discussions on the list on risks vs. merits of leaving backups on disk for extended periods of time, though.
Hope this helps, Frank --On Monday, May 20, 2002 10:02:31 -0500 Brad Felmey <[EMAIL PROTECTED]> wrote: > We're converting from Alexandria to Amanda. The differences are rather, > well, stark. > > I've been reading a lot of various online Amanda resources, but what I > really need to determine is holding disk requirements. I'm sure this > info is concisely covered somewhere, but I'm slogging through tons of > the same stuff over and over looking for it. I may even have looked > right at the info I need without recognizing it. > > May I respectfully request a pointer to a resource to determine my > holding disk requirements? > > Thank you, > -- > Brad Felmey -- Frank Smith [EMAIL PROTECTED] Systems Administrator Voice: 512-374-4673 Hoover's Online Fax: 512-374-4501
