Reading direct from Optical Media

OSVault can be configured to either stage files back to hard disk on access or to read directly from optical media for files not resident on hard disk.

Generally, the OSVault appliance needs to be installed either one way or the other, it won't support both types of file access. Once a system is configured as a staging (also called DMAPI) system, it is difficult to change that configuration. Also, once a system is configured for direct reads from optical disk, it is difficult to convert it to stage files.

Direct reads from media are accomplished via symbolic links that are on the hard disk and point to the optical disk file. The migration.c source code has a DEFINE called PURGEIT that, if defined, makes the migration program able to migrate files and replace them with symbolic links. When using direct reads/symbolic links, you do not use the "purge" program. The "purge" program is only used with staging configurations.

Generally, reading directly from optical media or staging files works well with Windows shares, but NFS shares require files to be staged back to disk. If you wish to read directly from optical disk and use and NFS share, you will have to NFS mount both the /cache share and the /archive share.