Backup Solutions

[Robert Brockway]

On Fri, 31 Aug 2007, I wrote:

> I strongly recommend periodic full backups (not justlast weeks changes). You 
> want to know your files are really there when a disaster strikes. Having full 
> backups makes a disaster recovery much simpler.

I've decide to expand on this a bit.  I follow the KISS principal for 
backups.  Keep it simple.  Disaster Recovery is a PITA even when you think 
you've thought of everything (I've had to do real DRs for clients several 
times including a restoration in the multi-terabyte range once).  Don't 
make the recovery any more complicated than it needs to be.

I backup virtually[1] everything on every box, including the OS.  When you 
are doing a DR in the real world you don't want to be having to debug 
application config problems or even driver problems.  Just back it up - 
backup disk is cheap and OS installs are comparatively small.  Just 
backing up /etc and expecting to recover from the latest version of 
packages won't work in many cases - config files can change & different 
compile time options may be used.

I set things up so that when I do a DR all I need to do it bring the 
restore media back on site, prepare the disks on the box, and start 
restoring.  Full restore first followed by the appropriate set of 
incrementals.  Then I run the bootloader and we're pretty much done.  If 
we are talking about restoration to an entirely new system them you can 
expect some driver issues once the restoration is done but they are not 
generally serious.  Linux copes with new hardware very well.  Not a bad 
idea to keep the original distro kernel around in case you need to boot 
the system on different hardware.

[1] There are some things I do not backup.  /tmp & /var/tmp, & mounted 
cdroms.  Sometimes a box may have a "scratch" filesystem which is not 
backed up - for example it may only contain iso images from the 'net that 
can be downloaded again if a disaster occurs.

Cheers,

Rob

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