Re: [Dump-users] Help with full and incremental dumps

[Scott E. <sc...@MI...>]

On Wed, 2 Jan 2008, Kenneth Porter wrote:

> Just saw your post on the CentOS list about this:
>
> <http://lists.centos.org/pipermail/centos/2007-December/091795.html>
>
> Another dump user pointed out to me the value of using LVM snapshots to dump 
> a "live" filesystem. You need a little extra space on the disk to hold the 
> filesystem changes while the snapshot is in effect (ie. for the duration of 
> the dump, and perhaps the verify if you do that).
>
> ------------ Forwarded Message ------------
> Date: Thursday, December 20, 2007 12:31 AM +0000
> From: "Keith G. Robertson-Turner" <dum...@ge...>
> To: Kenneth Porter <sh...@se...>
> Subject: Re: [Dump-users] Missing files on verify, hard link issue?
>
> Verily I say unto thee, that Kenneth Porter spake thusly:
>> --On Friday, December 14, 2007 2:16 PM -0800 Kenneth Porter
>> <sh...@se...> wrote:
>
>>> On my first attempt I still ended up with a couple of missing files
>>> in the  pool.
>
> I strongly suggest you investigate LVM, it'll save you a lot of hassle
> trying to dump a live filesystem.
>
> Here's a condensed version of my server's backup script, as an example:
>
> level=$(expr $(date +%u) - 1)
> lvcreate -l100%FREE -s -n var-snapshot /dev/cumulous/var
> mount -t ext3 /dev/cumulous/var-snapshot /mnt/snapshots/var
> dump -${level}u -z -E /mnt/WD_Passport/sky.backup/var.exceptions \
>  -f /mnt/WD_Passport/sky.backup/${level}/var.dump /mnt/snapshots/var
> umount /mnt/snapshots/var
> lvremove -f /dev/cumulous/var-snapshot
>
> It really is that simple. All you have to do is format your drive(s)
> with LVM, and remember to leave some unused slack at the end (I leave
> about 1GB, which has always been enough for that very busy server).
>
> -- 
> Regards,
> Keith G. Robertson-Turner
>
> ---------- End Forwarded Message ----------
>
>> From your CentOS post:
>
>> Trying to adapt the knowledge to a tape library...
>> 
>> /sbin/dump -0 -v -z2 -f /dev/nst0 /var/log
>> /sbin/dump -0u -v -z2 -f /dev/nst0 /home
>> 
>> I have a cron job that dumps the results to /var/log/dump.log, and a
>> review of the log file claims all went well.  Now for the restore...
>> 
>> I just tried playing with different options of restore, but could not
>> successfully restore anything.   I ensured I was in a scratch area so as
>> to hopefully not overwrite current files.
>
> What options did you try with restore? What tape positioning and library 
> commands do you use? (I believe mt is the command used to move the tape to 
> the desired dump file before issuing restore.)
>
> For testing, try the -C option (compare). I use that following every dump to 
> make sure the data got to the tape. (I'm using an external USB drive now, but 
> I used to use DAT tape on SCSI quite successfully.)
>

So my next question would be if I set up my filesystem withOUT LVM, and, 
considering it is an active machine, is there any easy way to incorporate 
LVM without having to redo everything?

Thanks.

Scott