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
}

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