ntbackup block size

[Guest Sam Casperson]

Hello all.

 

I have several branch servers that use ntbackup for nightly backups. These

backups are performed on Quantum DAT72 tapes, usually running on Adaptec SCSI

controllers. The OS for the servers are Windows 2003 Service Pack 2.

 

There seems to be a problem appearing with some of the tapes from the branch

servers. We regularly ship tapes to H/O for testing and restoring

information, but several of them can be read from our server at H/O. Our H/O

server is running on similar hardware and OS but is using backup exec 11.

When cataloguing the tapes, it gives and error about the block size being

used is incorrect.

 

I used the tape utility that comes with the DAT72 drives to find out what

information I can about the branch tape drives, and I came across that the

default block size used is 128kb for the units that produce the backups that

can’t be read. Also backup exec seems to be limited to 64kb block sizes.

 

I've done some tinkering with one of these servers, and with changing the

SCSI adapter, it reduced the block size to 64kb and the restoration works.

 

These branch server that appear to be using 128kb block sizes can backup and

restore ok on their own machines. But this doesn’t help me much is the

machine fails and I can't restore it on a different one. Also changing the

hardware on all of the machines that have this issue would be a pain in the

a$$.

 

Is there a way that I could force ntbackup to use a block size that I

specify, or does anyone have any other suggestions as to how I can resolve

this issue?

 

Thanks everyone!

Sam Casperson

[Guest cory@bluepointdesign.com]

Re: ntbackup block size

 

I'm working on a performance issue with IBM LTO-3 drives that is

currently focused on block sizes. If you find a way to cvhange block

size would you mind popping me a note?