I've been struggling with proper performance when duplicating images.

A recent test has shown me that performance drops but never increases throughout
the duplication.

The image I tested with has 16 fragments.
The 1st attempt at duplicating ran at about 0.5 meg/sec throughput.
Then I cleaned the tape drives and reran the same duplication (deleted the other
2nd copy with bpexpdate)
It then began transferring above 3meg/sec. (the report AllLogEntries will
display the speed at which each fragment is copied)
Near the end of the duplication (fragment 13) performance dropped below 2meg/sec
By the time it reached the last fragment performance was just above 1 meg/sec.

This leads me to believe that somehow the tape drive drops its performance based
on its ability to move the data at an acceptable rate without errors. I think
that when I clean the drives it must somehow reset the tapes and performance
will pick back up.

My backups seem to run at an acceptable speed so I can only assume that reading
the tapes is the problem. I ran my tests using images that were not multiplexed
to rule out the fact that multiplexing was the problem.

I've contacted Veritas support and StorageTek support. I'm hoping one or both of
these groups will be able to solve my problem.


If anyone can give me some advice regarding this problem please do... I would
really appreciate it.

Thanks