Sandeep,

> I am using L1000 Storedge connected to E3500 running Solaris 
> 2.7. For the
> past few days I have been fighting to make DLT7000 write with 
> compression
> [70 G]. I am sure I have correct settings in st.conf for DLT7000 with
> density set at 0x85 . I am backing normal data files [which 
> are gzipped] and
> are around 50 GB. It changes the tape after around 32 GB.

  The problem is the gzip! We have seen this in DLT7000's and DLT8000's too.
If you are using hardware compression on the drives, and you try to compress
an already compressed file (gzip, pkzip, even jpeg's) the data will actually
expand on you.

  I don't know a good way around this. Someone else may be able to tell you
if you can turn off the hardware compression for a particular backup. We
don't have enough of this problem to worry about it.

  The newer tape drives are supposed to be able to handle this better.
Theoretically, the LTO drives will sense compressed data, then they won't
attempt to compress that data when they put it to the tape. I'd like to see
that.

   Bryan


Bryan Bahnmiller
Agilent Technologies
(719) 590-3262