Backups with AMANDA
Background
We have two main file-servers (musashi, and yamato), which each perform their own backups Monday through Friday (typically). Musashi has a SCSI-attached HP LTO-1 Ultrium 230 (Aug. 2003) tape-drive, while Yamato has a replacement Ultrium 232 (Nov. 2006) tape-drive.
Amanda Server Configuration
The first step was to determine the tapetype entry, in /etc/amanda/Dailyxxx/amanda.conf; here are the results from two different tests on separate systems:
Ultrium 230
define tapetype Ultrium230 {
comment "HP Ultrium 230, produced by amtapetype"
length 101376 mbytes
filemark 0 kbytes
speed 13871 kps
}
Ultrium 232
amanda@trainwreck ~ $ amtapetype -f /dev/nst0 -e 100G -o
Writing 1024 Mbyte compresseable data: 37 sec
Writing 1024 Mbyte uncompresseable data: 72 sec
WARNING: Tape drive has hardware compression enabled
Estimated time to write 2 * 102400 Mbyte: 14400 sec = 4 h 0 min
wrote 3080192 32Kb blocks in 94 files in 7025 seconds (short write)
wrote 3096576 32Kb blocks in 189 files in 7511 seconds (short write)
define tapetype unknown-tapetype {
comment "just produced by tapetype prog (hardware compression on)"
length 96512 mbytes
filemark 0 kbytes
speed 13611 kps
}
Tape Drive Compression
Compression can be turned on or off using the mt tool noted below, then initiating the tapetype check; kill the tapetype check with ctrl-C when you've got enough info (takes quite a few minutes)
trainwreck ~ # mt -f /dev/nst0 defcompression 1 trainwreck ~ # su - amanda amanda@trainwreck ~ $ amtapetype -f /dev/nst0 -e 100G -o Writing 1024 Mbyte compresseable data: 42 sec Writing 1024 Mbyte uncompresseable data: 72 sec WARNING: Tape drive has hardware compression enabled Estimated time to write 2 * 102400 Mbyte: 14400 sec = 4 h 0 min amanda@trainwreck ~ $ logout trainwreck ~ # mt -f /dev/nst0 defcompression 0 trainwreck ~ # su - amanda amanda@trainwreck ~ $ amtapetype -f /dev/nst0 -e 100G -o Writing 512 Mbyte compresseable data: 38 sec Writing 512 Mbyte uncompresseable data: 39 sec Estimated time to write 2 * 102400 Mbyte: 15600 sec = 4 h 20 min