Backup technique

All backup clients must be online 24 hours a day and will be backed up automatically during the night. When a file space is backed up for the first time, a full backup of the entire file system is created. After that only incremental backups are made, meaning that only modified and new files are copied.
The clients need a 10Mb-Ethernet, 100Mb-Ethernet, or 1Gb-Ethernet adapter and must be registered in the DESY names-server.

When the scheduled backup time for a client is reached, the backup-server activates the TSM/ADSM scheduler process which is running permanently on this client. Some data is compressed in the client's memory (CPU consuming) and then stored by the TSM on tape cartridges STK9840 in a tape library STK Powderhorn.
The normal backup policy for public machines is: incremental backup every night, i.e. 7 times/week (other backup policies are possible, e.g. 1 times/week).
After all backups are done, the TSM server migrates the data from write-disk-cache to tape, every morning/day.
The TSM server holds up to 20 versions of a backed up file. Removed files are expired from the ``ACTIVE'' mode during the nightly incremental backup. After file deletion, TSM retains the last 10 file versions 100 days. The last file version will be held 200 days in an ``INACTIVE'' status.

The node administrators should monitor the TSM/ADSM scheduler log and the mounts and status of the backup file spaces, as well as ensure the proper operation of the ADSM backup system on their nodes. There are some usefully hints to help TSM/ADSM node administrators.

A backup filter is active: TSM/ADSM ignores e.g. all kinds of /tmp files and all .netscape/cache with the help of a file filter pattern. If a user or administrator knows of other files or file types which do not need backups, they should ask for an extension to the node backup filter file (only root user access).

Backups are made for:

     * user data on centrally or general managed multi-user systems ( AFS, Windows, Linux, ...)
     * general, centrally managed multi-user databases ( SAP/R3, Oracle, OSM, Objectivity, Mail, MS-Exchange, ...)
     * and for other important data on clients (only on special request, closed registration).
       A complete overview of all TSM/ADSM nodes see under: nodes.
       Please ask the local system administrator for details.

MOST of the disks or file-systems (300 TB? at DESY) will NOT be backed up, e.g: systems, binaries, experimental data, CD-ROM data, etc.
General rule: if a recreation is possible, no backup will be necessary.

File spaces requiring backup should not exceed the recommended maximum volume size.
Rule: the full restore (disasters recovery) of a file space should not exceed 10 hours,e.g.:


network interface

full restore speed

recommended max-size

files (230KB fsa)

data compress


3GB/h = 0.8MB/s

30GB Volume




8GB/h = 2.2MB/s

80GB Volume




22GB/h = 6.1MB/s

220GB Volume




? 64GB/h = 17.8MB/s

650GB Volume