[ale] Versioned backups are simple now.

[DJ-Pfulio]

Don't forget that ZFS actually validates what was sent to be written was
actually written to the disk.

If a file is corrupted and you don't realize it within the backup
versions, either the versions retained aren't long enough or the file
isn't THAT important.  Of course, regulatory mandates can alter this.

For a desktop, 60 days of versioned backups has been sufficient.
For higher risk systems, 180 days might be needed. If you like monthly
or yearly archives, that is easy. It is just storage space.

For off-site archives, rsync the rdiff-backup dirs to somewhere you trust.

But there are lots of ways to slice this sashimi.	

On 1/20/19 9:03 AM, Jim Kinney via Ale wrote:
> That's where the rolling backup/restore process is useful.
> 
> Of course there's a rabbit hole of depth of backup storage. Bit rot
> happens on tape, too. I've seen diff run between archivals of full
> backups as a deterrent to mylar-backed bit rot. The goal was to have two
> tape copies of each file.
> 
> The other process involved just a verified tape copy. So make a checksum
> verified full backup. Then copy that backup offline and reverify. But
> this does require two tape drives.
> 
> For the small scale setup, using nearline hard drives for main backup
> process and a selection of external drives for archival copies. Critical
> file archival on worm media like the m-disk dvds and blue-ray are very
> affordable.
> 
> LTO tape drive are fantastically expensive but highly reliable. The
> version 8 drives are $8k. Hmm. Maybe that's what the versioning is. The
> v6 drives were $6k and the v3 were in the $3k range. I am NOT looking
> forward to the v12 model. Yikes!
> 
> On January 19, 2019 7:29:38 PM EST, Steve Litt via Ale <ale at ale.org> wrote:
> 
>     On Sat, 19 Jan 2019 09:27:46 -0500
>     DJ-Pfulio via Ale <ale at ale.org> wrote:
> 
>         $ sudo rdiff-backup --force --remove-older-than 60D /Backups
> 
> 
>     Sometimes it could be years before you know a file got corrupted or
>     deleted.