[Veritas-bu] buffer settings for bpduplicate?

bpduplicate isn't *really* affected by those buffers oddly enough.

You need to play with the NET_BUFFER_SZ 
(http://seer.support.veritas.com/docs/183702.htm)

to improve your bpduplicate performance...

David

Quoting "Jeff A. Earickson" <jaearick AT colby DOT edu>:

> Hi,
> 
>    I have a Sun L20 tape robot with two DLT8000 tape drives, connected
> to a Netra 105 running Solaris 8, with NB 4.5.  I have tuned my Netbackup
> buffer settings per Veritas technote 183702 to be NUMBER_DATA_BUFFERS=16
> and
> SIZE_DATA_BUFFERS=65536.  When I took the NB Advanced Course, they talked
> about "waited for full buffer" and "waited for empty buffer" messages in
> the bptm logs, and how "waited for full buffer" messages are really, really
> bad -- because the tape drives will stop a lot and "shoeshine".
> 
>    The NUMBER_DATA_BUFFERS and SIZE_DATA_BUFFERS do a good job of
> minimizing
> "waited for full buffer" messages for ordinary backups, but I still get
> a ton of waits for bpduplicate jobs.  I would guess that that the size
> and/or number of buffers for a tape-to-tape copy within the robot are
> still not big enough to give me good performance.  The command I use
> for doing duplicates is:
> 
> bpduplicate -v -dstunit slate-dlt-robot-tld-0 -dp duplicates \
>         -hoursago 11 -L /tmp/dup2.output
> 
> and the originals are not multiplexed.  I've read the manpage for
> bpduplicate
> and don't see any option to specify the buffers settings for this job.
> 
>    Anybody have any good ideas as to what the buffer settings should be
> for a high-performance duplicate between two DLT8000's?  Any ideas on
> how to reset the buffer settings for bpduplicate, short of script
> manipulations before the bpduplicate job runs?
> 
> ** Jeff A. Earickson, Ph.D                         PHONE: 207-872-3659
> ** Senior UNIX Sysadmin, Information Technology    EMAIL:
> jaearick AT colby DOT edu
> ** Colby College, 4214 Mayflower Hill,               FAX: 207-872-3076
> ** Waterville ME, 04901-8842
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