Re: Homebuilt NAS Advice

[Stefan Monnier <monnier@iro.umontreal.ca>]

> And I disagree with you, because if you do not have RAID, you loose the data
> instantly and in best case your backup is a few hours old. Plus you have
> the effort to restore probably the last monthly, then the last weekly and
> then few incrementals - compared to replacing just one disk and letting it
> resync.

Again, this heavily depends on the specifics.

In my case, RAID would have been helpful once over the last 20 years
(and FWIW, I'm still using that disk that failed (after having created
a partition that covers about 4% of the disk and which encloses all the
sectors that can't be read/written any more ;-)

So in my experience it's rarely useful.  That doesn't mean it's not
worth it, tho.  For that you need to look even more at the details of
the actual upsides and downsides:

- I work on 3 machines "all the time" (one desktop at home, one at the
  office, plus a laptop), so if one of those machines dies I can just
  keep working with one of the other ones (and I have an extra laptop
  that I keep as hot spare).  W.r.t my servers, I similarly have 2 (one
  at the office and one at work, both of them keeping a copy of my
  backups), so if one dies, well, I just use the other until I can fix
  that one (and FWIW one of them tends to crash fairly often lately, for
  software reasons).
- Regarding backups: I wouldn't restore a full install from a backup,
  instead I'd clone one of my other machines.  But w.r.t
  full/incremental, I use `bup` which doesn't distinguish between those.
- More importantly, most of the things I work on are "backed up" several
  times a day on a remote server by virtue of being pushed to
  a Git repository or being stored in an IMAP server (which *does* use
  RAID, but that machine is not under my control).  So in the unlikely
  (but definitely possible) even that my machine dies, I won't lose very
  much work anyway.
- RAID would require extra hardware in my machines, for some of them
  that would be a non-trivial constraint (e.g. my BananaPi servers and
  my laptops).

RAID makes a lot of sense in many cases, but I don't think it makes
sense in mine.


        Stefan