[ale] Backup questions -- what to back up?

[DJ-Pfulio]

For nominal, daily, automatic, backups, I do the selected areas and keep
a list of packages (dumping any SQL DBs first).  In my testing of
restores, servers are working again in less than 45min.  This is about
the same amount of time having a bit-for-bit backup takes to restore for
me, without the huge waste of storage.

There is an issue with this method - if the box was hacked, important
information may not be included in the backups, so steps to mitigate the
break-in may not be possible.  I've seen where /tmp/ was used for
hacking scripts because the userid couldn't write anywhere else on the
box.  I don't know anyone who backs up /tmp or /var/tmp.  Do you?  The
scrips where after-the-break-in, but perhaps looking through them would
have provided hints to the attacker?

If it was a 1-time thing and I needed to restore ASAP, I'd do a complete
backup of everything (minus "special files") - using rsync. Restore is
just to rsync back the OS onto a new HDD, then do a grub-install and
update-grub - reboot and be happy.

When moving systems and taking the old HDD with me isn't possible, the
rsync method is what I use.  It often takes longer, but it is possible
to run the rsync's with the running system as the source, before the
final "good" rsync is run without the source file system active. This
can drastically reduce downtime to just a few minutes when swapping HW
completely.  The 1st rsync might take 15-90 minutes, but the 2nd one is
usually under 30 sec.  The only time that doesn't work is when huge
files are being synched, IME.  Large files seem to force rsync to copy
everything again instead of doing diffs.  Nothing you and Jim don't
already know.

Plus rsync behaves differently with local disk vs network copies.
Surprised me when it copied everything rather than doing diffs - sorta
defeated the purpose for using rsync. There are options to control this,
but the defaults ARE NOT SANE for local copies, IMHO.

Since all my production systems run inside VMs, being able to move to
another VM host isn't hard.  The physical machines aren't anything
special and have a fairly stock setup.  /var/lib/ just gets extra
storage. ;)

On 02/29/2016 12:12 PM, Derek Atkins wrote:
> Hi,
> 
> I'm working on configuring some backups via rdiff-backup, and I've got
> some style questions.  My main question is: do you back up /bin,
> /usr/bin, /lib, /usr/lib, and other "system" directories?  Or do you
> only backup /root, /etc, /var, and select areas, and keep a package list
> of the installed packages?
> 
> If you do backup the system directories (/bin, etc), what's the best way
> to restore the system?  I'm thinking disaster recovery, not "oops, I
> deleted a file and need it back"?
> 
> Thanks for your guidance,
> 
> -derek
> 


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