Sunday, March 29, 2009

AIX Backup in short and sweet

Aix is a unix based os developed by IBM and was originally released in the mid 80s for PC RT. When IBM released the RS/6000 in 1992, it released AIX 3.1 and built in is a mksysb script to do a full rootvg or OS backup. Other volume groups are not touched by this script. It was aimed at scsi tape drives. When booted from tape, the system would be restore rootvg to exactly what it contained when it was backed up. When finished, the system reboots. IBM never supported writing to cd but went directly to dvd. A mksysb can be written to dvd and then booted and restored from dvd. This function would be VERY helpful to linux releases or unix released. What was described earlier is simillar to a product in AIX called Network Install Manager - nim. Using nim, a root user can do a bootable backup to a remote system and then restore from that system. A nim restore is the fastest form of installing AIX and is used by manufacturing to preload systems. Today, at AIX 6.1, nim and mksysb are mature and trusted processes. Non rootvg volume groups are backed up using savevg. savevg is better than tar as it creates logical volumes the correct size and correctly names the mount points and then restores the data. Again, its a mature process. Even open files are backed up with mksysb and savevg although any save to the file after its backed up isn't reflected. A mksysb has 3 components, A boot image, a complete list of files and the actual backup. When the mksysb is taken, it compares what is on the list to what is on the tape in the backup. They must agree.

Another option is LVM snapshot for your system/important directories and then tar/pipe them to lzma (faster/better than bzip2). You can write the scripts yourself or search for somebody else's on google.LVM snapshotting allows you to also capture the logical volumes and only needs the space that the delta data would require. You can back up the snapshot and ensure a consistent state, then destroy the snapshot.


You can also try STORIX but it's not free