Re: Compression on Exb 8500

[Marty Shannon, RHCE]

Glen Eustace wrote:
 
 On Tue, 05 Feb 2002 18:35, you wrote:
  Try: man stinit and after you've created the proper device nodes
  (search the archive for an earlier post of mine), add post-install st
  /sbin/stinit to /etc/conf.modules.  You already have the proper density
  codes, so it shouldn't take more than a few minutes to get it all set
  up.
 
 Thanks for the info, I read your previous letter and am still a bit confussed.
 
 I only want the single mode on the drive, so didn't put a mode line in the
 stinit.def file, stinit complains it is missing.
 
 If I add a mode1, then it complains there is not device /dev/nst1, which is
 true it is /dev/nst0.
 
 It doesn't like mode0, and clues ?

Hmmm, if I said mode0-3, my bad.  Must be mode1-4, but you don't need
all of them.  You do, however, want to be certain to identify the drive
to stinit, using the manufacturer= and model= (which you get from
the kernel boot messages in /var/log/messages).  For instance, the
customized part of my stinit.def file for my AIT-1 drive:

manufacturer=SEAGATE model=AIT {
can-bsr can-partitions scsi2logical auto-lock
mode1 blocksize=0 density=0x30 compression=0# native, no compression
mode2 blocksize=0 density=0x30 compression=1# native, w/ compression
}

(note that you have your own density codes, and probably should not use
compression= for the Exabyte drives).  Also, after editing
/etc/stinit.def, do rmmod st, then modprobe st.  Oh, yeah, the
device files:

$ ls -l /dev | grep ' 9, ' | grep st0
crw-rw-rw-   1 root disk   9, 128 May  5  1998 nst0
crw-rw-rw-   1 root root   9, 160 Dec 11  1999 nst0c
crw-rw-rw-   1 root disk   9,   0 May  5  1998 st0
crw-rw-rw-   1 root root   9,  32 Dec 11  1999 st0c

stinit is smart enough to find them, no matter what you've called them,
but you must have both a rewind and non-rewind device for each mode you
specify.  If, in fact, you have more than 1 tape drive, and the drive
you're messing with is actually st1, increment all the device minor
numbers by 1 (1, 33, 129, 161).

Let me know if any of that helps

(Copied back to the list, as the problem continues to crop up for
folks.)

Marty
--
Marty Shannon, RHCE, Independent Computing Consultant
mailto:[EMAIL PROTECTED]

Re: Compression on Exb 8500

[Joshua Baker-LePain]

On Tue, 5 Feb 2002 at 5:51pm, Glen Eustace wrote

 It would seem that we have some kind of conflict with hardware and software 
 compression.  If both are on, the backups can not be restored. I have managed 
 to turn off software compression and that seems to cure the problem but would 
 prefer to do software and not hardware.
 
 I have tried turning off compression using 'mt -f tape setdensity 0x15', 
 which seems to work but doesn't stick, the next time amanda writes to the 
 drive it has gone back to 0x8c.
 
 This system is on RH6.2 on SPARC, is there anyway of permanently turning off 
 compression on the Exb8500 ?

Well, the drive should have some dipswitches -- check your hardware 
manual.  Alternatively, from the mt man page:

   defdensity
  (SCSI  tapes)  Set  the  default  density code. The
  value -1 disables the default density. The  density
  set by setdensity overrides the default until a new
  tape is inserted. Allowed only for the superuser.


-- 
Joshua Baker-LePain
Department of Biomedical Engineering
Duke University

Re: Compression on Exb 8500

[Marty Shannon, RHCE]

Glen Eustace wrote:
 
 It would seem that we have some kind of conflict with hardware and software
 compression.  If both are on, the backups can not be restored. I have managed
 to turn off software compression and that seems to cure the problem but would
 prefer to do software and not hardware.
 
 I have tried turning off compression using 'mt -f tape setdensity 0x15',
 which seems to work but doesn't stick, the next time amanda writes to the
 drive it has gone back to 0x8c.
 
 This system is on RH6.2 on SPARC, is there anyway of permanently turning off
 compression on the Exb8500 ?

Try: man stinit and after you've created the proper device nodes
(search the archive for an earlier post of mine), add post-install st
/sbin/stinit to /etc/conf.modules.  You already have the proper density
codes, so it shouldn't take more than a few minutes to get it all set
up.

Marty
--
Marty Shannon, RHCE, Independent Computing Consultant
mailto:[EMAIL PROTECTED]