Steven Hildreth <[EMAIL PROTECTED]> wrote:
>Hi, so here is the deal I am wanting to backup my two servers onto a single
>tape backup. I have a Redhat/Samba server and a redhat/mail/dns/router
>server.
>
>What I am doing now is having the Redhat/mail/dns/router server nightly
>smbtar all the shares on the Redhat/Samba server and then writing these
>smbtar's (along with tars created of its own directories) to a 4 gig SCSI
>tape.
There are a couple of other options that might be
easier/faster/better/whatever than using this method:
1) NFS mout (read-only) / on the server to be backed up. Then either back
up everything which would get the server with the tape drive and the other
one or perform two backups - one of the server with the tape drive
(excluding the NFS mounted filesystem from the other server) and the other
just the NFS mounted filesystem from the other server.
2) Backup the server without the tape drive using /etc/rmt and either rsh
or ssh. You'd either have to time it so the tape drive wouldn't still be
in use or use rsh or ssh from the server with the tape drive to kick off
the backup script on the other server.
There's obviously some setup required for each of these methods, but I've
experimented with both of them so yell if you want to try one.
>Seems that I have a problem with over 2 gig, is this because of a file limit
>with the smbtar? or just linux?
Yes, Linux has a 2Gb file size limitation at this time.
>I want this backup to be automated. To be able to just replace tapes daily
>and have crontabs ( as I do now) do the work and send me email reports of
>the outcome.
>
>I have NEVER been able to backup all of the Redhat/mail/dns/router server
>and then just untar it back to a newly installed and reboot and resume.
>Seems that I can only backup /etc /var/named /home /var/spool/mail and then
>rebuild the other stuff by hand.
>
>I guess my point, as I am sure you are wondering what it is, is this:
>How-Where-What for Simple, reliable backup from a single SCSI tape drive for
>two machines, one the machine the drive is one the other using a samba
>server. To be able to create a "restore" system to boot from a floppy
>re-fdisk and restore the tape and voila!
>
>Is this possible without the purchase of a third-party backup solution?
Yes (with a few caveats). I happen to use BRU, which is a commercial
backup product, but it should be doable with tar, cpio or other backup
software and/or a different tape drive. It's really the methodology that's
important, not the tools or hardware involved.
Now for the caveats:
In theory (and probably in reality) it's doable with a floppy disk, but I
decided to go a slightly different route. Yes you can get a working copy
of Linux on a single floppy with some tools to help recover from a crash,
but it's a pretty tight squeeze and there may not be room for the
backup/restore software and other things you may need, especially when the
server to be restored must use a remote tape drive.
I haven't had time to write up a good working description of how to go
about using my method, but I know it works because I've used it. In short,
it goes like this:
1) If necessary, re-partition the disk drive.
2) Install a *very* skeletal working copy of Linux to a "recovery"
partition on the hard disk using the CD-ROM or original media, whatever
that may be. Note: Whenever I setup a new server I leave a small (~250Mb)
partition at the beginning of the disk for this purpose. Yes, it's wasted
space during regular operation, but with today's large disk drives it
shouldn't be much of a strain. For drives that don't have this partition
already set aside, you'll probably need to re-partition anyway so why not
create the space then.
3) Install/configure any other services needed for backup (eg. backup
software, networking (if required for the restore), etc.)
4) Recreate the necessary directory structure of the original server,
mounting other filesystems to somewhere temporary, like /mnt/restore or the
like.
5) Restore from tape using /mnt/restore as the / directory.
6) Run lilo to update the MBR. (There are specific switch settings for this.)
7) Reboot and if all goes well, the server will be back to its backed-up state.
8) wipe the data from the temporary recovery partition (optional).
Obviously there are specific things for each step that need to be followed,
but that's the process in a nutshell. I've been threatening to write up
the whole mess as a web page, but I haven't gotten around to it yet.
This may or may not be to your liking or may be more complicated that you
want. It is a little involved but I've only had to use it once (knock on
wood) so far after a disk drive failed.
There are probably other methods that may work as well and be simpler, one
of which would be some of the so-called "one-button" recovery software
packages that generally require only a boot floppy and the backup tape. I
don't have any experience with them but I *think* most of them expect the
tape drive to be installed in the server, obviously a limitation for
you. I believe Enhanced Software Technologies ( http://www.estinc.com )
makes a 1 floppy, 1 tape full recovery product, but I haven't used
it. Check out their website and see if it's to your liking.
If you are interested in the full recovery process I could probably get
busy writing it as a web page, but it'll take me a bit.
-Eric
Eric Sisler
Library Computer Technician
Westminster Public Library
Westminster, CO, USA
[EMAIL PROTECTED]
Linux - don't fear the Penguin.
Want to know what we use Linux for?
Visit http://gromit.westminster.lib.co.us/linux
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