Backup server (old)
amanda.conf
- dumptypes
- dumpcycle
- estimate timeouts
- Tapetype definitions
disklist
tapelist
Exclude lists
This part has been moved to a separate page. See Exclude and include lists.
Device configuration
Tapetypes
Tapetype definitions are specified in amanda.conf configuration file. The tapetype definition provides AMANDA how much it is supposed to be able to store in a tape (length), how much space is wasted at the end of a dump image with the EOF mark (filemark) and how fast the tape unit is (speed).
The most important parameter is length, since AMANDA may decide to delay a backup if length is too small, but, if it is too large, AMANDA may end up leaving dumps in the holding disk or having to abort some dump.
Filemark is important if you have many disks, particularly with small incremental backups. The space wasted by so many filemarks may add up and considerably modify the available tape space.
The speed is currently unused.
AMANDA provides the amtapetype utility to calculate the size of a tape, to generate a "tapetype" entry for your amanda.conf.
Specifying the appropriate tape device, but beware that it may take many hours to run (it fills the tape twice ...). Make sure you do not use hardware compression, even if you plan to use hardware compression in the future. amtapetype writes random data to tape, and random data will expand instead of compressing, therefore you'll get an estimate that's smaller than expected.
Some tapetype definitions are available here.
Changers
This part has been moved to a separate page.
See Changers.
RAIT
RAIT is an acronym for "Redundant Array of Inexpensive Tapes", where data is striped over several tape drives, with one drive writing an exclusive-or-sum of the others which can be used for error recovery. Any one of the data streams can be lost, and the data can still be recovered.
This means that a 3-drive RAIT set will write 2 "data" streams and one "parity" stream, and give you twice the capacity, twice the throughput, and the square of the failure rate (i.e. a 1/100 failure rate becomes 1/10,000, since a double-tape failure is required to lose data).
This means you can back up partitions as large as twice or four times your tape size with Amanda, with higher reliability and speed.
RAIT can also be used to mirror a backup to two drives, even when one of them is a virtual tape and the other is a real tape.
See Rait for a more complete description.
File driver/Disk backups
This driver uses files on disk as virtual tapes. Amanda can write to and read from virtual tapes, just like real tapes. A bunch of virtual tapes can even be manipulated with a changer.
Possible Uses
- Test installations: You can easily explore the rich features of Amanda on systems without tape drives.
- Inexpensive installations: Without buying a tape drive you can enjoy the benefits of Amanda and backup to a bunch of internal or external harddisks connected with Firewire or USB. You can create CD/DVD-sized backups which you can burn onto optical disks later.
- Disk-based installations: You can use the file driver to backup onto a set of virtual tapes hosted on a bunch of hard-disks or a RAID-system. Combined with another Amanda configuration that dumps the virtual tapes to real tapes, you can provide reliable backup with faster tapeless recovery. This is called "disk-to-disk-to-tape" backup by some people today.
See File driver for a more complete description of virtual tapes, and their use.
Server-side and Client-side encryption
This section has been moved to a separate page.
See Encryption.
Custom Compression
- compress client custom
- Specify client_custom_compress "PROG"
- PROG must not contain white space and it must accept -d for uncompress.
- compress server custom
- Specify server_custom_compress "PROG"
- PROG must not contain white space and it must accept -d for uncompress.
- sample dumptype:
define dumptype custom-tar {
global
program "GNUTAR"
comment "root partitions dumped with custom compression"
compress server custom
server_custom_compress "/usr/bin/my_gzip"
priority low
}
- I have tested custom compression using bzip2. Dumps works fine. Amrestore has a glitch on which
the image gets uncompressed correctly and written to a temp file but gets a broken-pipe error. I am investigating the problem.
Tape hardware compression
This section has been moved to a separate page.
See: Hardware compression.