The drive doesn't have any dip switches - I even took the drive out of the encosure and couldn't find anything.
I copied the wrong mt command over - Where I'm at now is looking at stinit ant the /etc/stinig.def file to create a /dev/nst0l device which disables compression - I'm in the middle of another test right now and can't try it out just yet - but if this works for me I'll send it to the list. We have a ton of these Sun SDLT 220 drives floating around and want to use them. I ran some tests using hardware compression and wasn't impressed with the results so I'm trying it with it off. ------ Original Message ------ Received: Thu, 29 Sep 2005 02:29:47 PM MDT From: Gene Heskett <[EMAIL PROTECTED]> To: [email protected] Subject: Re: Disable Tape Compression > On Thursday 29 September 2005 12:08, Christopher Davis wrote: > >I'm using Amanda on Fedora Core 4 with a Quantum SDLT 220 tape drive - I > > want to disable hardware compression but I'm not sure of the best way > > to do that. > > > >I can issue a command mt -f /dev/nst0 defcompression 1 which seems to > > work (amtapetype doesn't give me the warning about hardware compresion) > > but as I understand it this change goes away as soon as I change tapes. > > Meaning each time I insert a new tape I have to re-enter this command? > > > defcompression 1 turns it on, not off. And there is probably a > dipswitch of jumper setting someplace on the drive to turn it on > permanently IF thats what you want. Check your docs on the drive. > > However, running hardware compression hides the tapes true size from > amanda, so you have to make an educated guess in setting the > tapetypes 'size'. Amanda meas7ures the amount of data sent down the > cable to the drive, and if amanda is doing the compression, which can > handily beat the hardwares compression ratio in many cases, then > amanda knows exactly how much the tape can hold. > > So, generally speaking, we don't recommend hardware compression. To > give you an idea of how good the 'compress best' can be, I have a > report of from of my recent runs that, with a 48 entry disklist, some > compressed and some not, still put a bit over 17GB of real data in > about 7.5GB of storage space used. It won't do that every night of > course, but often enough to pay for the cpu power it takes. > > > >How can I make the change permanent so that I don't have to worry about > >manually changing a settting? > > > > > >Any ideas or help would be much appreciated. > > > > > >Chris > > -- > Cheers, Gene > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author) > 99.35% setiathome rank, not too shabby for a WV hillbilly > Yahoo.com and AOL/TW attorneys please note, additions to the above > message by Gene Heskett are: > Copyright 2005 by Maurice Eugene Heskett, all rights reserved. > >
