On Monday 25 November 2002 11:56, Ronan KERYELL wrote: >I'm in trouble with a HP SureStore DAT40 (DDS-4) since I cannot > write compressed partition past 16GB instead of achieving the > theoretical 20GB. > >I guess it is because the drive is in hardware compression mode, > but I do not know how to explain it to the drive... :-) > >I've read the man st and is does not look as clear as on > Solaris... > >gaudi:~# ls -al /dev/nst0* >crw-rw---- 1 root tape 9, 128 Mar 14 2002 /dev/nst0 >crw-rw---- 1 root tape 9, 224 Mar 14 2002 /dev/nst0a >crw-rw---- 1 root tape 9, 160 Mar 14 2002 /dev/nst0l >crw-rw---- 1 root tape 9, 192 Mar 14 2002 /dev/nst0m > >I've tried each /dev/nst0* without success : > >gaudi:~# tapetype -f /dev/nst0 >wrote 524508 32Kb blocks in 1604 files in 9324 seconds (short > write) wrote 505626 32Kb blocks in 3102 files in 11965 seconds > (short write) define tapetype unknown-tapetype { > comment "just produced by tapetype program" > length 17021 mbytes > filemark 403 kbytes > speed 1576 kps >} >gaudi:~# tapetype -f /dev/nst0a >tapetype: could not rewind /dev/nst0a: No such device or address >gaudi:~# tapetype -f /dev/nst0l >tapetype: could not rewind /dev/nst0l: No such device or address >gaudi:~# tapetype -f /dev/nst0m >tapetype: could not rewind /dev/nst0m: No such device or address > >Hmmm... Strange... > >Any help in the audience ? :-) >Thank you,
In addition to the reply message posted by Bernhard Beck, you should be aware that in earlier DAT drives, the MRS occasionally mentioned in the propaganda, records to the tape in a hidden header block, the status of the compression setting when the tape was last written. What this means is that you will have to use a means external to amanda to turn off the compression (this in addition to disabling it via the dip-switches the links in the message from Bernhard, to the docs on howto do that). If this isn't done, then when amanda re-reads the tape id block, the compression will be turned back on. So in addition to turning it off via the dip-switch setting, each tape previously written to in the compressed mode will require that you run a little script you can probably write yourself, and which does approximately this, paying attention to the /dev/tapedevice used: 1 read out the tape label using dd. dd if=/dev/st0 of=scratch count=1 2 issue all mt legal combinations of turning the compression off, see man mt. mt -f /dev/nst0 defcompression off mt -f /dev/nst0 datcompression off mt -f /dev/nst0 compression off there may be more, or less in your version of mt. 3 using dd, write enough raw data from /dev/zero to the tape to cause the drive to do a buffer flush, thereby re-writing that hidden header with the non compression state in effect. dd if=/dev/zero of=/dev/st0 bs=32k count=65535 4 restore the tapes name header dd if=scratch of=/dev/st0 count=1 5 by now, if the drive has a compression status LED, often labeled "DC", it should be off. 6 verify the header can be read dd if=/dev/st0 count=1 which should print the header to the screen. 7 advance the magazine to the next tape needing this treatment if there is more. 8 repeat 1-7 until out of tapes that need it. 9 re-run the tapetype program to get your new value for the tapes actual capacity, it should be closer to 20gb than before. -- Cheers, Gene AMD K6-III@500mhz 320M Athlon1600XP@1400mhz 512M 99.19% setiathome rank, not too shabby for a WV hillbilly