AFS backups with Amanda

Mitch Collinsworth

Cornell Center for Materials Research

Motivation

A flexible, automated backup system for both AFS and non-AFS filesystems

Existing alternatives

AFS backupADSM/TSMOthers?

AFS backup

Complex and difficult to automate typical implementation uses home-

grown scripts errors recovery requires manual

interventionCan’t share tapes with non-AFS

backups

ADSM/TSM

Good automation bus costly for smaller sites

No server for free OS’s (Linux, FreeBSD...)

Data integrity dependent on a database “Good” tapes are worthless if database

is compromised

Amanda

A backup manager, not a backup program

Manages native backup programsFreewareTapes are in native formatTape library support (extensible)

Amanda...

Optimizes daily tape usage spreads full dumps across the backup cycle

Optimizes daily backup window Multiple dumps in parallel to a holding disk

Optimizes tape speed/usage Keeps tape streaming by feeding from the

holding disk

Amanda...

Easy to add filesystems to backup list

Easy to add tapes to the tape cycle

Easy interactive restores from any client

Compression in software or hardware

Amanda - deficiencies

Windows support (smbtar) currently a kludge

No Mac support

No tape spanning or appending

Amanda - advantages

Share tapes with non-AFS backupsMultiple backups in parallelAutomated error recoveryDegraded mode - tape errors don’t

stop the whole show

Advantages...

Free, runs on any unix

Supports for tape libraries

Keeps high capacity tapes streaming

Implementation

Use ‘backup dump’ or ‘vos dump’ ?

Volume sets?

Dumpdates equivalent

Implementation...

Needed functions Estimate Backup Index generation

Recovery dumptool (Ken Hornstein) might be

useful. Needs to run in a single pass so can be pipelined.