tape record bigger than supplied buffer

Alex Zbyslaw xfb52 at dial.pipex.com
Tue May 31 03:56:38 PDT 2005


Damian Sobieralski wrote:

>>2) See if you can't find some option to match the bacula record size
>>to that of your tape drive.  Dump, for example, has a -b option e.g.
>>"-b 64" to set its record size.  I'm puzzled by you only seeing three
>>messages though.  Why would three buffers be smaller and not the
>>rest?
>>    
>>
>
> That's a good question that I don't know the answer to.  I thank you
>for the response.  I'll see if I can get a bit more information by
>restoring the data for us to work with.  When you say match the record
>size to my tape drive's, is this something that should be listed in my
>tape drives literature?
>
>  
>
Well, I'm guessing yes, but only based on that error message.  I know 
older tape drives had fixed record sizes, and maybe some kinds of new 
ones do too.  My DAT drive does variable sized records, because it has 
native compression, but yours may not.

You could also try "mt -f /dev/sa0" and see what it says.  I can't 
remember off had if it shows anything useful but it only takes seconds.  
(I'd check, but I'm in the middle of upgrading hardware/software and the 
tape drive isn't connected up yet).  You could also try man 4 sa which 
talks about fixed and variable block sizes.  (As far as I know, there is 
a limit of 64k for the record size, but this was info from the 4.X 
series, so I reserve the right to be wrong :-)

--Alex



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