Date: Fri, 23 Jan 2009 23:44:27 +0100 (CET) From: Oliver Fromme <olli@lurza.secnetix.de> To: freebsd-stable@FreeBSD.ORG, bms@incunabulum.net Subject: Re: A nasty ataraid experience. Message-ID: <200901232244.n0NMiRmM098646@lurza.secnetix.de> In-Reply-To: <497A0BCA.5070904@incunabulum.net>
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Bruce M Simpson wrote:
> [...]
> I also now understand that I can't rely on RAID alone to keep the
> integrity of my own data -- there is no substitute for backups,
That's 100% true. RAID -- even true hardware RAID -- is
*never* a substitute for backup. Consider:
- Fire.
- Theft.
- Lightning strike or power surge.
- The cleaning woman knocks the tower over.
- ...
In all of those cases, chances are that both disks in the
RAID mirror die. Also, as you mentioned, it doesn't
protect agains human errors ("rm *" in the wrong directory
and similar things).
Backups should always be made to media that can be taken
offline and stored in a safe place: Tape, optical disks,
hard disks in swappable drive trays, or external drives.
> I just wish there were realistic backup solutions for individuals
> trying to do things with technology right now, without paying over
> the odds, or being ripped off.
I think the best solution is to use standard hard disks
in external enclosures (USB, Firewire, eSATA). They're
fairly cheap these days and easy to handle. Furthermore
they're quite fast.
For a very simple backup solution I recommend to buy at
least two USB disks and use them alternating, so you
still have a good backup on the shelf when something
catastrophic happens while the other one is connected
to your computer.
As for the backup software, I simply use "cpdup" (from
ports/sysutils/cpdup) to duplicate the file systems.
It's fast (copies only changed files), and you can
easily restore files after an "rm *" by simply copying
them back with cp. (The only gotcha is that cpdup
doesn't preserve "holes" in sparse files, but cases
are rare where you need that.)
Of course you can also treat the disks like tapes and
dump(8) to the raw device (or tar, cpio, whatever),
if you prefer.
YMMV, of course.
Best regards
Oliver
--
Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M.
Handelsregister: Registergericht Muenchen, HRA 74606, Geschäftsfuehrung:
secnetix Verwaltungsgesellsch. mbH, Handelsregister: Registergericht Mün-
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FreeBSD-Dienstleistungen, -Produkte und mehr: http://www.secnetix.de/bsd
"We will perhaps eventually be writing only small modules which are identi-
fied by name as they are used to build larger ones, so that devices like
indentation, rather than delimiters, might become feasible for expressing
local structure in the source language." -- Donald E. Knuth, 1974
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