Backing up to tape

Frank Leonhardt freebsd-doc at
Wed Apr 25 17:54:07 UTC 2018

Old LTO drives are cheap and offer a good $/Gb. And I could do with some 
archiving. But it's been a while since I used tape (System V IIRC). Are 
my assumptions correct?

If I plug a SAS drive in to an HBA it'll just appear as /dev/sa0 (or 
similar) - right?

Then I can backup everything with tar -cf /dev/sa0 /* - right?

Well I could if my HD was small or the tape was big, as the tar 
documentation says "There is not yet any support for multi-volume 
archives." Does the tape driver take care of this (i.e. "Insert Tape 2 
and press a key") or does it just bomb?

I like tar for archiving stuff, but is dump/restore the way to go? 
Probably not, because you can't specify files really.

And I'm probably more likely to backup ZFS datasets these days, so would 
be relying on the tape driver to handle multi-volume tape sets.

One idea I have is to write a very quick and dirty program and pipe the 
output of tar to it, and have it write to the tape unit - pausing for 
tape changes. This is so obvious that it must already exist, or be a bad 
idea for a subtle reason I haven't spotted.

Is anyone using tape able to confirm any of this one way or another?

Thanks, Frank.

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