Making Backups to DVD

Audience: Systems Administrator

Date: June 9, 2002

A DVD can be an inexpensive way to make data or system backups. The current list price of a DVD is $1,000, compared to $2,000-$6,000 for tape.

Creating a system backup on DVD is different than making one on tape. With a DVD, you use the new AIX mkcd command (or smit mkcd). The smit mkcd options are straightforward, with the exception of the "DVD sized image", which should be set to "yes".

Limitations

DVD limitations include:

• DVD storage capacity is limited to about 4 GB, compared to 20+GB for tapes.
• The mkcd command requires extra disk space, as it stages the backup data on disk. My understanding is the staging size is the size of the backup. So, if the backup size is greater than 2 GB, you'll need to change the ulimit (or fsize=-1 in /etc/security/limits) for non-root users.
• DVD backups may take longer than tape. DVD's are rated between 1-3.6 MB/sec, compared to MB/sec for most tapes.

For more information, see:

http://publib.boulder.ibm.com/doc_link/en_US/a_doc_lib/cmds/aixcmds3/mkcd.htm http://publib.boulder.ibm.com/doc_link/en_US/a_doc_lib/aixins/aixinsgd/intro_backup_cdrom.htm

Finally, the mkcd requires the public domain software package "cdrecord-1.9.0.0" to burn CD's. This software is is available from the following website:

http://www.rge.com/pub/systems/aix/bull/aix432 /