On 4.5 the limitation of a backup from local disk to a tape is bpbkar which
has a block size of 32kb internally. this is fixed and cannot be tuned,
whereas tar or cpio you can set a much larger blocksize.

in netbackup 5.0 this blocksize is 128k, but still not tuneable. best thing
is to get multiple bpbkar processes running in parallel by breaking the
filelist into streams of drives / mounts or files -

ie rather than backing up


/usr

run

/usr/*

or

/usr/[a-m]*                     ( i think you can do this on unix clients, but 
not windows )
/usr/[n-z]*

and you will get a different backup stream for each directory. This isn't a
good example on /usr - you have to make sure the spec you pick doesnt
generate too many streams which are very small, and also make sure the
wildcard spec has no 'gaps' otherwise some point down the line you might
find you haven't been backing everything up.

regards
mark


-----Original Message-----
From: veritas-bu-admin AT mailman.eng.auburn DOT edu
[mailto:veritas-bu-admin AT mailman.eng.auburn DOT edu]On Behalf Of Chadwick
Leung
Sent: 14 March 2004 06:23
To: veritas-bu AT mailman.eng.auburn DOT edu
Subject: [Veritas-bu] LTO2 backup speed just up to 5 MB/sec under
Netbackup 4.5


Greeting!

I have installed a Sun L8 autoloader which replaces a Sun L9 model . The L8
has been successfully installed and can operate without problem. However,
the average throughput is just up to 5 MB/sec under Netbackup 4.5.

I tried to TAR a 1.2 GB file direct to the LTO2 tape, it took about a
minute. Under Netbackup, backing up the same file take about 4 mins. 30 sec.

Any idea?

Best Regards,
Chadwick Leung

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