On Thu, Nov 1, 2012 at 3:27 AM, FSG WD Andre Paetzold
<[log in to unmask]> wrote:
> On Wed, Oct 31, 2012 at 13:27:49 -0500, Ken Teh wrote:
>> Do you still use mt and tar for backups on LTO drives or is that so uncool compared to bacula? Does that mean I'm uncool if I confess I still do? ;)
"mt" and "tar" are built into most open source tape management
solutions. I ported Amanda to Solaris long, long, long ago, and it
still works well. It's also available with commercial support at
www.zmanda.org"
> Yes, we even still use 'find | cpio' ... ;)
> But nowadays, when the files become bigger than 8GB, we must switch our scripts to 'tar'
>
> To increase the performance of the tape-drive, we use 'tar --blocking-factor=2048' to write
> with Blocksize of 1MB, but with our new HP LTO5 Tape Blade (connected via SAS)
> we got input/output errors, so we must switch to Blocksize of 512KB... :(
> On our HP LTO5 MSL4048 (connected via FibreChannel) it is still possible to use 1MB Blocksize.
Oh, getting down into the guts! I still remember my lamentations that
the Exabyte drives had no "EOT" marker, the end-of-tape marker used to
show where writing had stopped, which was usually two "EOF" or
end-of-file markers in a row. I went nuts writing wrap-arounds to find
the end of the tape to write the next dump on a tape I'd just
inserted!!!!
The problem was that I had a closet full of old magtape with
irreplaceable research data, the tape drives the oldest tapes were
compatible with were going away, and I needed the material on new
media where it would be stored. Enter the "Amanda" software, and a
chunk of time adapting it to the Exabytes. It very effectively uses
tar (and now, star for SELinux settings as well) to write the tapes,
and *the technology is stable*. Unlike many commercial solutions, any
idiot 10 years from now can still read the tapes even without an
expensive sotware package that may not run on any OS they own.
These days, I first dump to disk with "rsnapshot", because large,
consumer grade disk is so cheap now. That lets me keep the last few
days or weeks of snapshots and make them available to users without
having to give them tape access, they can just access their NFS shares
from the cheap storage. And I can run the tape against *that*.
>> Do you still need mt if you use a package like bacula?
>>
>
> We need 'mt' to rewind the tape in case of an error, to retry it, and at the end of
> the backup to eject the tape from drive, so the operators only have to grab the tape
> or the see there was an error, if the tape isn't ejected...
Binigo.
>
>> Thanks!
>
> So long,
> André
>
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