Re: [Dump-users] Live filesystem summary

[Eric R. <ros...@ma...>]

Quoting Sean Kelly <se...@sh...>:

> I have used the following method under Solaris and don't know off hand
> whether Linux would support it.  I therefore present it here for
> discussion and would like to point out that I'm fairly sure someone
> has thought of this before me and I take no credit for any ideas...

It should work fine under Linux.  I used to do the same thing for OpenVMS
systems.

BTW, Solaris 8 (with patches) and above (without patches) support 
file system snapshots, so this shouldn't be needed any more if you have 
the extra disk space to make snapshots.

Also, I left out of my previous message about using LVM that you do indeed
have to have some spare disk space laying around for the snapshot to
live on.  Fortunately, you only need a small fraction of the actually
used disk space, so this isn't a real big deal for most users.  But it
is a factor to consider.
 
> Under Solaris I have at times (ie. when there's been no budget for a
> "real" solution) used software RAID (Solstice Disksuite) to run a
> three way mirror of each partition onto two other disks. 

I've only ever done this with two-way mirrors, and it works fine that
way, except:

> This should, of course, work with just two disks in the mirror but you
> expose yourself to risk when you detach one half for the backup.

Yes, true, but for most people it is worth the risk compared to the
cost of extra disk space.

> I have not fully tested the recovery of a system backed up in this
> way.  That is, as ever, left as an exercise for the reader.

*grin*

Please folks, remember that no matter how you do your backups, you
need to test them to make sure they work, and that you can restore files
and/or filesystems from them.  Backups are worthless if you can't restore
(recover) from them!

> Thanks,
> 
> --
> Sean Kelly <se...@sh...>

-- 
Eric Rostetter