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Re: Guide(s?) to backup philosophies

On Tue, Mar 14, 2017 at 05:54:06PM +0000, Glenn English wrote:
> On Mon, Mar 13, 2017 at 12:38 PM, Dan Purgert <dan@xxxxxxxx> wrote:
> > David Christensen wrote:
> >> On 03/11/2017 07:10 AM, Richard Owlett wrote:
> >>> I've vague ideas of what backup pattern(s) I might follow.
> >>> I'm looking for reading materials that might trigger "I hadn't thought
> >>> of that" moments.
> >>>
> >>> Suggestions?
> I didn't see anybody talk about incremental backup (the backup
> consists of current versions as well as earlier ones -- often earlier
> work can replace erroneous or lost current work. Or work you don't
> notice is gone for a few days.). There are 2 I know of, and one (and
> probably many more) that may do that:

Having been there and done that, I can assure you that having a
live snapshot system -- rsnapshot or btrfs/zfs native tools --
is more fun and less work for everyone.

As a bonus, they can all send snapshots to remote systems or
detachable media.

> It backs up to a single disk.
> It's GUI is kind of cutesy and a bit hard to use.
> It's Mac only.
> Macs change every few minutes. But I've been using it since it came
> out (one of the Leopards), and it's not changed, AFAIK.

On Macs, this is the way to go. But! You don't need to back up
to a single disk. You can back up to a Linux system running
AppleTalk, and those volumes can sit on RAID or ZFS or whatever
you want. Recommended.


> It can be configured to use many different pieces of medium.
> It writes to tape or disk. I don't know if it does cloud.

You can pretend a remote server is a set of disks. I wouldn't.

> I've been using Amanda with tape for over a decade. No probs. Backing
> up and recovering. I've never had to do a bare metal restore, though.
> Nor have I ever tried to recover from one of its tarballs.

Not much fun. Especially compared to self-service or nearly
self-service from snapshots.

> I've been on Amanda and tape from the beginning, back in the dark
> ages, but I suspect it'd be happy to write to a handful of large(ish)
> thumb drives. Another way of getting an incremental backup is to
> mirror an entire system every day to a different device from a
> collection of removable media (like thumb drives). That'd be a problem
> for the likes of Google or Amazon, but might work well for a small
> system.

Thumb drives are terribly unreliable, but cheapish. Treat them
like tapes and never write over them, and assume that some
percentage will just die.