Hi Francis

Cheers I now got a better understanding from the replies.

Thx

On Wed, 2006-05-10 at 11:53 +0200, Francis Galiegue wrote:
> Le Mercredi 10 Mai 2006 11:13, Chuck Amadi Systems Administrator a écrit :
> > Hi List
> >
> > I have been running a Daily and Monthly config on two SuSE SLES 9
> > servers using DDS-4 TAPES.
> >
> > I have a problem with the Monthly archives doing full backups (uptp 98%
> > full) I am looking at a complete back strategy using a dedicated rack
> > backup server LTO or DLT drives.
> >
> > But for now I am going to use DDS-5 36GB Native tapes at the moment I am
> > using DDS-4 20GB Native tapes for my DAT/DDS drives which as stateds are
> > getting rather full for MonthlySet full backups for archiving.
> >
> > Thus if I run the command amtapetype -f /dev/nst0 as previous did for
> > DDS-4 tapes.
> >
> > When this is done I receive an analysis of the tape device and the tape
> > types.
> > As the output from amtapetype may well take many hours as it writes to
> > the complete tape a couple of times So is it worth running the above
> > command.
> >
> > The previous output is something like this for my current DDS-4 tapes
> > which I am using and works.
> >
> > define tapetype tape-dds4 {
> >     comment "just produced by tapetype program(hardware compression
> > off)"
> >     length 19015 mbytes
> >     filemark 399 kbytes
> >     speed 1570 kps
> > }
> >
> >
> > Thus should I still run amtapetype -f /dev/nst0 command to get the
> > precise  definitions and add the new one I have just created, or just
> > amend/hack the MonthlySet config file.
> >
> > tapetype tape-dds5
> >
> > define tapetype tape-dds5 {
> >     comment "just produced by tapetype program(hardware compression
> > off)"
> >     length 37537 mbytes # guess or gooogle for something practical
> >     filemark 623 kbytes
> >     speed 1570 kps
> > }
> >
> > or as per this URL
> > http://wiki.zmanda.com/index.php/Tapetype_definitions#DDS-5_170_meter_tapes
> >
> > define tapetype tape-dds5 {
> >    comment "DDS5 (hardware compression off)"
> >    length 37537 mbytes
> >    filemark 623 kbytes
> >    speed 1758 kps
> > }
> >
> >
> > I have hardware compression set to off as I was told that Amanda uses
> > software compression in my case tar not gzip thus cant use hardware
> > compression as well
> > turn off datacompression run mt command below that controls magnetic
> > tape
> > drive operation.
> >
> >
> > server:~ # mt -f /dev/nst0 status
> >
> > server:~ # mt -f /dev/nst0 datcompression 0
> > Compression off.
> >
> >
> > I have digested the list and told to use one *or* the other of hardware
> > and software compression;
> > general consensus on the list is that software compression is better if
> > you can spare the cycles.
> >
> > Thus what is the best way to get my MonthlySet to use DAT/DDS-5 tapes.
> >
> > Cheers
> 
> Hello,
> 
> FWIW I use a HP-DAT72x6 tape changer which uses 36/72GB tapes. I use it with 
> hardware compression DISABLED (I use "compress server fast" instead). I ran 
> amtapetype and obtained this:
> 
> define tapetype HP-DAT72 {
>     comment "Produced by tapetype prog (hardware compression off)"
>     length 37511 mbytes
>     filemark 625 kbytes
>     speed 1758 kps
> }
> 
-- 
Unix/ Linux Systems Administrator
Chuck Amadi
The Surgical Material Testing Laboratory (SMTL), 
Princess of Wales Hospital 
Coity Road 
Bridgend, 
United Kingdom, CF31 1RQ.
Email chuck.smtl.co.uk
Tel: +44 1656 752820 
Fax: +44 1656 752830