[DM-MUG] Fwd: Dr. Mac's Guide to Backing Up Your Mac -- The Mac Observer

[kristau]

RsyncX, I believe, can help reduce the amount of backup drive space
needed.  It uses hard linking to make incremental backups of your
data.  This means you can have several backup rotations which appear
to be full backups, but actually consist of links to the files that
have not changed since the last backup, plus the files which have
changed.

For example, say you have two files and a 7 day backup rotation,
starting on Sunday.  Let us say "File One" changes on Tuesday and
Thursday and "File Two" changes every day.

By the end of the week, there are only three copies of "File One" on
your backup media -- the original taken on Sunday, one taken on
Tuesday and one taken on Thursday.  There are 7 copies of "File Two"
at the end of the week -- one for each day it changed.

In the folder for Monday's backup, the "copy" of "File One" that
appears there is actually a link back to the file taken on Sunday.  In
Friday's backup folder, "File One" links back to Thursday's version.
That way, you don't have multiple, identical copies taking up space on
your backup.  Of course, in every day's backup folder, there is a
different copy of "File Two" because it changed every day.

This can greatly reduce the amount of storage space needed --
especially when backing up folders like /System and /Applications
which do not often change.  Depending on how much "change" takes place
over the course of your rotation and how long of a history you keep,
you could get by with an external backup drive which is only 150% to
200% the size of the data you need to back up.

On 3/4/07, Ray Bowler <rbowler at mchsi.com> wrote:
> kristau,
>
>
> Yours is a good backup strategy and on my wife's I have one routine
> which she can use whenever she wants to do so. I use Intego's
> Personal Backup for this one.
>
> Still I like a full clone done once a week using SD and then I can
> boot from it. The big negative is that even when doing a backup which
> just synchs it can take a while. Also you have to have large drives
> for the backups when you make two or three.  The big positive is that
> when her HD went south I was able to switch to the clone to operate
> for a few days.
>
> At 1:21 PM -0600 3/4/07, kristau wrote:
> >Since we are sharing backup strategies, here's mine:
> >
> >I do not back up the System or Applications folders, just my User
> >folder and various detachable media such as a USB flash drive and a
> >small external hard drive.  My reasoning is I can re-install the OS
> >and applications from discs or downloads.  Because this is my home
> >system, time to restore is not as critical as it would be for a
> >business or production system.
>
> --
> Ray Bowler
>
> rbowler.home.mchsi.com
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-- 
Tired programmer
Coding late into the night
The core dump follows

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