On Mon, 27 Jan 2003 19:47:21 -0600
will trillich <will@serensoft.com> wrote:
> On Mon, Jan 27, 2003 at 11:03:47PM +1100, bob parker wrote:
> > My idea is that after a disaster I'd make a minimum debian install,
> > restore $HOME, /usr/local. After that I'd reinstall my packages from the
> > list I gathered and then selectively restore /etc to get my configs back
> > the way I had them.
> sounds like a reasonable plan. got a script or two you'd care to
> share? :)
Something that might make those archives a little more secure would be the
inclusion of parchive into the mix. You'd have to use an archiver that splits
the archive up into manageable sized chunks (I prefer rar but it might not be
for everyone).
parchive is used mainly on Usenet to provide a method for people to
retrieve lost data from the data they have gotten. An example would be
someone sends out 200 JPG images and 3 never make it to your news server.
You'd grab the 197 jpgs that were there, the main par file, 3 of the
additional par files and it would be able to reconstruct the remaining 3
images without requesting a fill from the original poster. I'm not sure how
it works but it is much like how the parity drive on a RAID allows the RAID to
reconstruct lost data from a drive failure.
parchive does have its limits. Each parchive file is the same size as the
largest file, you can have only 255 par files and you nee one par file per
file lost regardless of size. This is why there is an almost perfect marriage
between rar and par. rar allows the user to split the archive up into chunks
of uniform size so the par file is the same size as the archive files save the
very last one. Also since there is the 255 "lost files" limit archiving the
files means you just keep the archive parts below 255 and you're fine. The
normal ratio of par files to real files is 10%.
While this is used a lot in usenet it can be used for backups. Imagine
burning a CD and that CD gets a scratch. Some files will be lost. But you'd
need to lose the original files and the par index and more par files than you
lose of the originals to be unable to recover the lost data. That is far
better that just losing the original data outright.
--
Steve C. Lamb | I'm your priest, I'm your shrink, I'm your
ICQ: 5107343 | main connection to the switchboard of souls.
To email: Don't despair! | -- Lenny Nero, Strange Days
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