OSVault support for WORM media

Testing is just about complete on this update to OSVault to support BD-R, DVD+RW, DVD+R, DVD-R and CD-RW media. There is a new migraiton program called "batch_migration" that complements the existing "migration" program.

Batch_migration is used just like "migration" and will copy files in a block from hard disk cache to optical media. "batch_migration" uses the same database of optical media to figure out which media to use (archive.media) and uses the same "inventory" program to figure out what media is loaded into the library. The "batch_migration" has been tested with 50GByte BD-R, 25GByte BD-R, 4.7GByte DVD+RW, 700MB CD-RW, and 4.7GByte DVD+R.

"batch_migration" reads thru the files stored in /cache and locates either the oldest or largest files to migrate. Oldest is the default. By default, batch_migration will only a maximum of 2000 files onto a piece of optical media. "batch_migration" will try to fill the optical media, but you should specify a minimum amount of data required before an optical burn begins to avoid wasting optical disk space.

"batch_migration" requires temporary hard disk space to create an ISO9660 image before the burn of the optical media starts, so it checks to make sure that free space exists. You can specify a different workspace location with the "-w" flag (the default is /var/tmp). DON'T PUT YOUR WORKSPACE in /cache, it will run slowly.

The current testing version of "batch_migration" is set to only do a single session to optical media. This works in most deep archive situations, but we realize that some customers may not generate enough data at a time to hold off migrating to optical only when a full disk is available. So we will be adding multi-session support in the next release. Multi-session support means, for example, that while using 50GByte media, you can move smaller amounts of data to a single disk over several sessions, rather than waiting for a full 50Gbytes on hard disk before migrating.