[Bacula-users] LTO 8 Slow write speeds

[Udo K. <ba...@in...>]

Am 11.04.25 um 15:54 schrieb Gilles Van Vlasselaer:
> I can't seem to get Maximum block size = 1024K to work, I can't label the tapes either with btape or bconsole;
>
> When I revert it to 512K, the labeling works as expected, maybe the drive isn't capable of managing 1M block sizes?
>
> Whilst being in the btape CLI, I was running test and when Max block size is set to 512K I get the following;
>
> Doing Bacula scan of blocks:
> 1 block of 524224 bytes in file 1
> End of File mark.
> 2 blocks of 524224 bytes in file 2
> End of File mark.
> 3 blocks of 524224 bytes in file 3
> End of File mark.
> 1 block of 524224 bytes in file 4
> End of File mark.
> Total files=4, blocks=7, bytes = 3,669,568
> End scanning the tape.
> We should be in file 4. I am at file 4. This is correct!
> The above Bacula scan should have output identical to what follows.
> Please double check it ...
> === Sample correct output ===
> 1 block of 64448 bytes in file 1
> End of File mark.
> 2 blocks of 64448 bytes in file 2
> End of File mark.
> 3 blocks of 64448 bytes in file 3
> End of File mark.
> 1 block of 64448 bytes in file 4
> End of File mark.
> Total files=4, blocks=7, bytes = 451,136
> === End sample correct output ===
> If the above scan output is not identical to the
> sample output, you MUST correct the problem
> or Bacula will not be able to write multiple Jobs to
> the tape.
>
> When I removed the Max Block size property the sample and scan output are identical, should I be worried?
>
>

Hi Gilles,

If the tape drive does not accept 1024K block size stay with 512K. The btape test looks all good to me. If you demand a block size of 512K the output cannot be identical to a sample 64K block size, right? The important parts are blocks per file, file count / EOF marks.

HTH, Udo