--On Thursday, June 16, 2005 23:59:28 -0500 Michael D Schleif <mds AT helices 
DOT org> wrote:

> Earlier this year, my HP DAT tape drive had problems, and I replaced it
> with a Compaq/Sony SDT-9000.  Mostly, I am still using the same DDS-3
> tapes that I was using, and retired some and added some.  My old records
> show that I was getting nearly the full 12GB uncompressed tape length.
> 
> Since the tape drive change, I have wondered why I didn't seem to be
> getting all the data on some tapes.  Clearly, with Amanda, some days it
> just doesn't want to send a full 12GB to tape; but, mostly, I have been
> seeing <9GB going to tape, and balance sitting in holdingdisk.
> 
> Today, I did this:
> 
>     # time sudo -u backup amtapetype -e 12g -f /dev/nst0 -o
>     Writing 32 Mbyte   compresseable data:  37 sec
>     Writing 32 Mbyte uncompresseable data:  35 sec
>     Estimated time to write 2 * 12288 Mbyte: 26880 sec = 7 h 28 min
>     wrote 298832 32Kb blocks in 76 files in 10632 seconds (short write)
>     wrote 310628 32Kb blocks in 158 files in 10840 seconds (short write)
>     define tapetype unknown-tapetype {
>         comment "just produced by tapetype prog (hardware compression
> off)"
>         length 9522 mbytes
>         filemark 0 kbytes
>         speed 908 kps
>     }
>     
>     real    364m39.451s
>     user    0m2.724s
>     sys     0m28.719s
> 
> 
> What is going on here?
> 
> How can I get a full 12GB tape length?
> 
> What do you think?

Are you positive hardware compression is off?  You might want to look into
Gene's frequent postings about disabling compression when tapes have 
previously been written compressed.
Are you actually hitting EOT on your backups, or is it just the result
of your tapetype setting the length to 9.5GB?  If you're not already
hitting EOT, try changing the length in your tapetype to 12GB and see
if more is written.

Frank

> 
> -- 
> Best Regards,
> 
> mds
> mds resource
> 877.596.8237
> -
> Dare to fix things before they break . . .
> -
> Our capacity for understanding is inversely proportional to how much
> we think we know.  The more I know, the more I know I don't know . . .
> --



--
Frank Smith                                                fsmith AT hoovers 
DOT com
Sr. Systems Administrator                                 Voice: 512-374-4673
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