DLT4700 density - how to get 40GB/tape

DLT4700 density - how to get 40GB/tape

Post by Randy Marchan » Fri, 17 Apr 1998 04:00:00



We have an Ultra 140, running Solaris 2.6, Solstice Backup 5.0.1 and it
has a DLT 4700 autoloader (7 cartridge capacity). We have the drive
loaded with CompactIV tapes which supposedly yield 40GB density.
The Solstice Backup device name is /dev/rmt/1mbn.

We're trying to get the 40GB capacity but are not able to do so. The nwadmin
utility seems to indicate we're getting slightly over 20GB/tape.

We see conflicting information about the density capacity of  the
DLT4700. The sun www site DLT4700 spec page says the read/write
compatibility is 20GB for a CompactIV tape. Yet, the product overview
page for the DLT4700 says the drive can store up to 280GB which is the
7*40GB/Tape figure. Which doc should we believe?

So, how do we set up Solstice Backup and the DLT4700 to give us the 40GB
capacity/CompactIV tape? Has anyone else run into this problem?

        TIA
        Randy Marchany
        VA Computing Center
        Blacksburg, VA 24060

 
 
 

DLT4700 density - how to get 40GB/tape

Post by Andreas Sinderman » Fri, 17 Apr 1998 04:00:00



> We have an Ultra 140, running Solaris 2.6, Solstice Backup 5.0.1 and it
> has a DLT 4700 autoloader (7 cartridge capacity). We have the drive
> loaded with CompactIV tapes which supposedly yield 40GB density.
> The Solstice Backup device name is /dev/rmt/1mbn.

Try /dev/rmt/1cbn which should switch on compress mode.

Andreas

 
 
 

DLT4700 density - how to get 40GB/tape

Post by Mike Marsha » Fri, 17 Apr 1998 04:00:00



>> We have an Ultra 140, running Solaris 2.6, Solstice Backup 5.0.1 and it
>> has a DLT 4700 autoloader (7 cartridge capacity). We have the drive
>> loaded with CompactIV tapes which supposedly yield 40GB density.
>> The Solstice Backup device name is /dev/rmt/1mbn.
>Try /dev/rmt/1cbn which should switch on compress mode.

And try pressing the button on the front of the drive which
specifies the highest density. They seem to default to lowest,
and/or default to whatever was last written to the tape.

After high density tracks have been written to a particular tape,
the drive will default to high density whenever that tape
is inserted...

-Mike

 
 
 

DLT4700 density - how to get 40GB/tape

Post by Oliver Hilgendo » Sun, 19 Apr 1998 04:00:00


On 16 Apr 1998 16:07:48 GMT, Randy Marchany


>So, how do we set up Solstice Backup and the DLT4700 to give us the 40GB
>capacity/CompactIV tape? Has anyone else run into this problem?

40GB is the compressed capacity. Native is 20GB.
 
 
 

1. 20/40GB tape drive getting terrible compression

Greetings,
    I have a customer with an RS/6000 S7A running AIX 4.3.2 and the
latest
patches and microcode, including the microcode for the 20/40GB tape
drive.
They are complaining that they can't fit anywhere near 20GB on a  tape.
In
fact, they say that the 9GB of data they are trying to dump is taking 3
tapes!
    They are using a utility from Filenet to write the data, not
something simple
like tar or mksysb.  I intend to run out there and use the same tapes
and tar
and see if I see the same results.
    They are using 170 meter tapes, which I believe is correct for this
model
of tape drive.  They are using the default parameters for the tape
drive; I
don't believe they have inordinately tampered with anything.

Any advice would be appreciated.

John Schneider

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* Lowery Systems, Inc.
* 1329 Horan                  Disclaimer: Opinions expressed here are
* Fenton, MO 63026                   mine and mine alone.
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