[nzlug] Raid

[Daniel Lawson]

Dirk Pilat wrote:
> Hiho,
>
> after the discussion about dual booting with raid/fakeraid, may I ask
> whether there is any benefit for me as a homeuser to have a raid
> setup? I regularly backup my homefolder and the HD that contains the
> data accessed by all my OSS's (music/movies/phothography).
>
> What benefit would Raid give apart from extra data security (and maybe
> speed)? 

Backups and RAID are also orthogonal technologies.  RAID doesn't protect
you against your power supply catching fire and burning your entire pc,
harddisks included.  RAID protects you from single (in some cases
multiple) disk failures.  Backup protects you from user stupidity
("whups, I just did rm -rf * ~ instead of rm -rf *~"), and from
entire-machine/environment failure[1]

Other than that, if you have regular backups[2] for all your data you
care about[3], the main benefit RAID gives you over backup-and-reinstall
is that your system is available immediately after a disk loss, as
opposed to having to wait until you can buy a new disk, then install
your OS, setup your applications, etc.  For business cases the benefits
are massive - a days downtime could cost a business a lot of money, and
the chances of a new server + OS install + data restore happening in a
day are pretty slim. More like 3 to 7 days, realistically.

For a home user, unless you can't afford to have a machine down, or
don't want to, or aren't skilled enough to rebuild your systems
yourself, then a well maintained backup is probably just fine.

[1] assuming your backups are stored elsewhere; if they are on the
machine next to the original, and your house burns down, you just lost
everything.
[2] and they actually work, and you can restore from them ...
[3] and you make sure you keep this list of data up to date ...