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

-- 
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