Eric, The mode select can be accessed through the mt commant, either with the setdensity or compression option. (Some drives use one, some use the other.) The mt status command will tell you if you're currently compressed, usually.
To use a tape without hardware compression in Amanda, I've had pretty good luck with setting the status with MT, then using amlabel to label the tape. It seems to stay uncompressed after that. Good Luck. Paul > -----Original Message----- > From: Eric Sproul [mailto:[EMAIL PROTECTED]] > Sent: Thursday, March 28, 2002 2:37 PM > To: [EMAIL PROTECTED] > Subject: disabling compression on external drive? > > > Hi all, > I've been away from the list for more than a year, but I'm > back for some > more help. ;) > > I'm setting up Amanda on my fileserver at home, mainly to back it up > locally, but I also have a couple other machines that I will do as > well. I'm using an external drive, a Seagate STD624000N, aka the > Scorpion 24, with DDS-2 tapes. It's running under Linux > (nst0) and the > drive shows up as > Vendor: ARCHIVE Model: Python 04106-XXX Rev: 7550 > > I'm just at the point where I'm running tapetype to get > accurate figures > for my conf file. I want to use software compression, so I > need to make > sure the drive is not doing it in hardware. There appears to be no > jumper or DIP switch setting for data compression. Reading > the manual, > there appears to be such a switch on internal models, but the > only thing > it says for external drives is "the SCSI Mode Select command > can switch > the drive into compressed or uncompressed mode for writing data > regardless of the position of the jumper..." > > I'm not familiar with the "mode select" command. Is there a way for > Amanda to do this whenever it writes to the drive? I tried > using what I > thought was the device corresponding to mode 3, nst0l (var. blocksize, > no compression), but got "could not rewind /dev/nst0l: No > such device or > address" from tapetype. But it's there when I do an ls. I'm > concerned > that if I just use nst0, and the drive defaults to hardware > compression, > then it will screw me up. > > Any help would be appreciated. > Thanks, > Eric > >
