Re: LTO support

[Brad Spencer <brad%anduin.eldar.org@localhost>]

Pouya Tafti <pouya+lists.netbsd%nohup.io@localhost> writes:

> I'm looking for a low cost offsite backup solution for my teeny local NAS (couple of TiB of redundant ZFS RAIDZ2 on /amd64 9.2_STABLE) for disaster recovery.  Seemingly affordable LTO-5 drives (~EUR 250; sans libraries) pop up on eBay from time to time, and I thought I might start mailing tape backups to friends and family.  Being rather clueless about tape, I was wondering:

[snip]

> - are there reliable strategies to split a larger ZFS volume across several smaller cartridges (LTFS seems not to support splits)?

[snip]

The general answer would be "not really"..  if you mean "zfs send" as
the method of getting the ZFS fileset or zvol and if you mean native to
ZFS itself.  I can't remember anything quite like this, but I can
imagine a simple program existing that would take a "zfs send" on stdin
and write to tape noticing when an EOF occurred and prompt for a new
tape.  The concept is baked into dump for FFS, but that may not be
desirable or even possible to use for ZFS in any manor.  I also don't
remember if something like tar would be usable when writing directly to
tape.  If tar did support tape switching well enough you may be able to
make use of it for ZFS filesets, but zvols probably need not apply...

The other way to do it would be to make sure that you used ZFS filesets
and zvols that could fit on your tape and just "zfs send" them
individually, but I do realize that may not be possible in the use case
you have.


I tend to take the negative view of tape and while I do realize that
they still exist, I really wish they didn't having had to suffer with
them for a lot of years in professional $DAYJOBS.  It would seem to be
simpler to just use a hard drive or some other random block storage now.
Large drives (possibly larger than any LTO tape you can get) with slow
access times which are fine for backups are pretty inexpensive now.



-- 
Brad Spencer - brad%anduin.eldar.org@localhost - KC8VKS - http://anduin.eldar.org