[sf-lug] Backups and such (was Re: South African Linux sites experiencing Ransomware attacks.)

[Michael Paoli]

Nowadays, my generally recommendation for most any typical
"home" type environment - backup to drive(s) - be they spinning rust
and/or SSD.  USB "thumb" drives and optical media - too slow and/or
unreliable, and not cost effective (especially at moderate to larger
scales).  Interface?  If one can do it with [e]SATA that would
typically be best, though USB - especially >=3 / SuperSpeed is
mostly "quite good enough" for backup(/restore) purposes
(however many would well argue not to use general active OS
filesystem storage over USB interface).

For *much* larger environments, magnetic tape may still make sense.
I know for quite a while I used mag tape (... QIC (with decicated
controller - SCSI also good/okay, not that "floppy controller"
based goop), DDS/DDS[234...?].  But eventually such no longer made
economic sense for smaller scales.  E.g. a good quality tape drive
to reasonably back up TBs of data will cost typically thousands of
dollars.  Most of us don't do enough "home" environment backups for
that to start to make economic sense.

So, personally ... I do "full" backups - nominally about monthly,
that get rotated off-site.  And often more frequent lesser
backups (on-site and/or less than full).  I also do *multiple*
backups.  My rule-of-thumb - at any given point in time, at absolute
minimum, there should be two complete full sets of off-site backups.
That generally means at least 3 such sets of media (drive or drives).
That way, even when one set is on-site, there's still at least two
full sets off-site - that includes all the stated and points in time
of any rotations.  Never less than 2 full sets off-site.  And, ... why?
Murphy.  Backups/media fail.  Disaster may strike when backup
media is on-site as part of a backup/rotation.  And if one's risk
tolerance is low, more sets of backup media, and additional off-site
location(s).  Disk is pretty cheap these days.  How much is all your
data worth to you? ... or if it went bye-bye, how much would you have
been willing to invest to not have had it go bye-bye?

And ... test - periodically test backups.  As if oft said, it's not
the backups that matter, but the restores - if you can't restore, your
backups don't much matter.  So do at least "enough" testing once in
a while ... I typically recommend at least enough statistical restore
testing to give one sufficient confidence in being able to restore,
relative to one's risk tolerance level.

> From: "Akkana Peck" <akkana at shallowsky.com>
> Subject: [sf-lug] Backups and such (was Re: South African Linux  
> sites experiencing Ransomware attacks.)
> Date: Thu, 12 Sep 2019 16:33:41 -0600

> Rick Moen writes:
>> Quoting Steve Litt via Tech (tech at golug.org):
>
>> > I've been making off-system and offsite backups only twice a year,
>> > clearly not enough. Most of the reason is that it's still murder to
>> > burn data, especially encrypted data, to blu-ray.
>
> Eek -- is blu-ray known to be longer lived than other optical media?
> I lost a bunch of photos many years ago that I'd deleted from my
> hard drive because I'd archived on multiple CDs, only to learn
> that none of my less-than-three-years-old CD archives would read.
> I no longer trust optical media for backups. Even aside from being
> slow and a hassle to burn.
>
>> One alternative is to do backup to a number of USB-connectable external
>> hard drives, used in rotational fashion.
>
> That's what I do.  Currently all spinning disks because they've been
> so much cheaper, but SSD prices have come down a lot, and recent
> research into drive longevity suggests that factors likely to cut
> SSD longevity (like temperature) are different from those that can
> cut spinning disk longevity (like magnetic fields), so I'm planning
> to add at least one SSD to the rotation.