Some drives can have the compression turned on by a drive setting so 
that it uses compression, regardless.  Did any of your drive settings 
change?

I agree with a previous poster in that you should do some kind of a test 
to determine how much data is being written to a tape before it moves on 
to a new tape.

bob944 wrote:

>>Date: Tue, 18 Apr 2006 10:42:58 -0400
>>From: "Carlisle, D Renee" <dcarlisle AT paychex DOT com>
>>    
>>
>
>  
>
>>I checked all that and it looks good=2E  Sg=2Econf is 
>>identical, major numb=
>>ers and minor number convention on the HP looks the same 
>>(they don't exist =
>>on sun)  no mention of compression or errors in bptm=2E  Our 
>>issue is that =
>>if we don't figure this out by Friday, we will be out of 
>>tapes=2E=0D=0A =0D=
>>    
>>
>
>What makes you believe that hardware compression is not working?
>Testing how many copies of a repeatable data set go to a newly expired
>tape before a second tape gets used, and repeating that (same tape, same
>data, same client) with 1 1.5:1 or 2:1 difference would be a clear
>indication.
>
>Didn't you mention that you had changed to a new (partitioned) library
>and drives, and were getting what you suspect is no h/w compression on
>one side of the library?  I'd want to know the library's contribution to
>your issue by testing.
>
>AFAIK, hardware compression is solely controlled by a SCSI command which
>sets the mode; the bits for which you see in the multiple-mode fields in
>Solaris st.conf entries.  That's a driver function.  On Solaris, you can
>look in messages on startup and see if the capability bits and modes you
>expect are what are reported.  
>
>I'd suggest proving the compression assertion first, then getting
>support people for the drive/library/drivers involved.  
>
>
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>  
>


-- 
Jack L. Forester, Jr.
UNIX Systems Administrator, Stf
Lockheed Martin Information Technology
(304) 625-3946