Alastair:

I use the same drive on HP/Compaq Tru64 UNIX.

1.  Do NOT use the hardware compression.  See the archived for an
exhaustive discussion of this topic.

2.  Uncompressed capacity of this drive is around 40 GB +/- 2GB.

Using a compressed tape device which uncompressible data will actually
reduce capacity, since recompressing compressed data makes it expand.

Best wishes,

Don

Donald L. (Don) Ritchey
E-mail:  Donald.Ritchey AT exeloncorp DOT com


-----Original Message-----
From: Alastair Neil [mailto:aneil2 AT gmu DOT edu]
Sent: Friday, January 16, 2004 2:17 PM
To: 'amanda-users AT amanda DOT org'
Subject: amtapetype


I just ran amtypetype -f /dev/rmt/0bn, a Sun Storedge L9 autochanger
and recieved the following:

define tapetype unknown-tapetype {
    comment "just produced by tapetype prog (hardware compression on)"
    length 34169 mbytes
    filemark 28 kbytes
    speed 1787 kps
}

I'm confused because I believed this to be a DLT8000 drive which should
be closer to 80 MBytes compressed, and certainly the speed is not what I
expected either. I ran amtypetape -c -f /dev/rmt/0bn and amtypetape -c
-f /dev/rmt/0cbn and received nearly identical output:

amtapetype -c -f /dev/rmt/0cbn
Writing 256 Mbyte   compresseable data:  27 sec
Writing 256 Mbyte uncompresseable data:  56 sec
WARNING: Tape drive has hardware compression enabled
Estimated time to write 2 * 1024 Mbyte: 448 sec = 0 h 7 min
 amtapetype -c -f /dev/rmt/0bn
Writing 256 Mbyte   compresseable data:  25 sec
Writing 256 Mbyte uncompresseable data:  56 sec
WARNING: Tape drive has hardware compression enabled
Estimated time to write 2 * 1024 Mbyte: 448 sec = 0 h 7 min

Host is a Sun E250, with HVDS adaptor.

Does anyone have experience with this drive?


-- 
Alastair Neil
Unix Systems Administrator
IT&E Labs
George Mason University 
(703) 993-3953


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