Using Tape Drives and Optical Disk Drives as Storage Devices

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Using Tape Drives and Optical Disk Drives as Storage Devices

Using tape drives or optical disk drives as storage devices provides a long-term, inexpensive way to store your data. You can store tapes and optical disks offsite or in a protected vault. They provide virtually unlimited storage capacity because you can always purchase new media. Tape and optical disk drives access data sequentially, which slows down backup and recovery.

If you are using tape drives or optical disk drives as storage devices for backups of your storage spaces, It is recommended that you reserve one device for your continuous logical-log file storage volumes. The other devices are available to receive data from storage-space backups.

Important:

When the currently mounted tape becomes full, ISM requires operator intervention to change tapes. The request to change tapes appears in the ISM log. You use the ism_watch command to monitor ISM for tape-change requests. To automate tape changes during unattended backups, you can use NetWorker or other storage managers that support advanced devices.

Warning:

You must use no-rewind tape devices because ISM writes a file mark on the storage volume at the end of each backup and then appends data onto the storage volume based on the position of the file mark. (A backup operation might contain several save sets.) If you use a rewind tape device, your backups will appear to have completed successfully but your tapes will contain only the last save set. The current save set overwrites the previous save set and data is lost.