Fwd: HomeUserBackup Feature Specification

[Aigars Mahinovs]

Hello all,

I am the author of SBackup, I normally do not read this list (as I am
not an Ubuntu developer), but since this discussion involves my
software and it has been brought to my attention I think it would be
useful for me to participate, so please CC me on this topic.
(Never mind that, I had to subscribe to get the email through :P )

A backup software should solve three types of failures:
1. Software failure or user failure where a piece of data is destroyed
leaving rest of the data intact;
2. Hardware failure - hard drive crash, lightning strike to the PC, a
commode falling on to the computer;
3. Disaster failure - hurricane, house fire, nuclear attack, ...

With each level the cost of protection for the failure goes up and
probability goes down. The cost is: software development cost,
software work cost, additional hardware cost, user work time cost.

Solution to the first failure type is simple and easy to automate -
local hard disc backups. It is easy to code, trivial to set up and
requires no maintenance at all. This is the current level of SBackup.

Solution to the second failure type is twofold - either backup to
remote server (easy to code, easy to set up, automatic, no
maintenance, already done in SBackup) or backup to removable media
(quite easy to code, easy to set up, non-automatible, bothersome to
maintain). If a system would ask me to change and label CDs in my disc
drive every day, I would bear with it for a week and then I would
probably turn it off or at least make it once a week. Thus long term
effectiveness of such backup is reduced by user laziness.

Third failure type is purely user operation (unless we want to provide
them remote servers to backup to) and thus is mostly outside the scope
of SBackup. We can only try to advise the user of importance of such
measures and let him decide what to do.

My plan for further development of SBackup includes backup to
CD/DVD/USB media as one of the first two priorities for next version
(the second being an applet to show backup progress and status). To
overcome the user laziness factor I plan to simply do automatic hard
drive backups and then once a month recommend user (with a
notification similar to upgrade notification) that making a hard copy
of a backup snapshot (on CDs/DVDs or USB drives) would be very
recommended. The same message could also give tips for marking and
safekeeping of such media backups.

Also another planned feature that is essential to making sure that
users do not turn off automatic backuping after some time is backup
size control - removing incremental backups that are older then a
month and removing all backups that are older then 3 months is planned
(both times configurable). As alternative I might try to implement a
gradual degrading scheme (keep at least one backup per day for last
month, keep at least one backup per week for last three months, keep
at least one backup per month for half a year, keep at least one
backup per year forever), but I am not sure that I will be able to
come up with a user friendly enough configuration interface for that
scheme.

I would be very happy to hear any constructive criticism and feature
suggestions as I plan to do a slight refactoring of SBackup and thus
now is the best time to come up with thing that would influence the
new architecture of the system.

--
Best regards,
    Aigars Mahinovs        mailto:aigarius at debian.org
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