Re: [gentoo-user] How to compress lots of tarballs

[antlists]

On 30/09/2021 00:17, Rich Freeman wrote:
> On Wed, Sep 29, 2021 at 5:48 PM Wols Lists<antlists@××××××××××××.uk>  wrote:
>> An LVM snapshot creates a "copy on write" image. I'm just beginning to
>> dig into it myself, but I agree it's a bit confusing.

> So, snapshots in general are a solution for making backups atomic.
> That is, they allow a backup to look as if the entire backup was taken
> in an instant.
>
> The simplest way to accomplish that is via offline backups.  Unmount
> the drive, mount it read-only, then perform a backup.  That guarantees
> that nothing changes between the time the backup starts/stops.  Of
> course, it also can mean that for many hours you can't really use the
> drive.
>
> Snapshots let you cheat.  They create two views of the drive - one
> that can be used normally, and one which is a moment-in-time snapshot
> of what the drive looked like.  You backup the snapshot, and you can
> use the regular drive.

Yup. I'm planning to configure systemd to do most of this for me. As a 
desktop system it goes up and down, so the plan is a trigger will fire 
midnight fri/sat, and the first time it gets booted after that, a 
snapshot will be taken before fstab is run.

Then I'll have backups of /home and /. I won't keep many root backups, 
but I'll keep /home until I run out of space.

And that's why I suggested if you want a separate backup rather than a 
collection of snapshots, you snapshot the backup and use in-place rsync. 
Of course that still means you need to quiesce the bit you're copying, 
but you could back it up piecemeal.

Cheers,
Wol