Questions about swapping in hardware (disaster recovery) solution..

[Paul Schulz]

Some follow-up...

The problem appears to be that the 'sysklogd' service is hanging, as I
only have to kill the service (/etc/init.d/sysklogd stop) and the
system startup process continues, and then everything works again.

On Dec 4, 2007 2:07 PM, Paul Schulz <pschulz01 at gmail.com> wrote:
> Greetings all!
>
> I have an interesting server problem..
>
> We (at work) are installing a new server and at the same time
> preparing backup hardware should something go wrong.. The plan is to
> do nightly backups to a disk in such a way that should something go
> wrong we can then swap in replacement hardware and/or disk, and take
> off from where the backup was done.
>
> So.. I trying to create a Ubuntu-server system which is portable
> across identical hardware, but where serial-numbers/MAC addresses will
> have changed.
>
> It is almost there, with just a couple of snags..
> - grub and fstab need to refer to device names rather than UUID's (easy to fix).
> - 'udev' wants to keep network device names around (looks easy to fix)
> - sysklogd does not start up properly, which causes logins to stop
> working (interesting to debug).
>   Restarting sysklogd allows logins to occur.. but I get the following error:
>
>     syslogd: unknown priority name "exec"
>
> It's the last one I need to get to the bottom of (hence my question),
> but other than this.. the idea, as a concept works quite well for us
> (details below).
>
> Does anyone have any suggestions?
> [Hardware is DELL 1950 1U servers with 2x 72GB SAS drives (non-RAID)]
>
> Cheers,
> Paul
>
> -- Disaster recovery methodology --
>
>   Two servers (S1,S2, geographically separated),
>   with two disks in each (diskA, diskB and diskC, diskD) + a couple of
> spare identical drives.
>
>   Main server:
>   - S1-diskA, S2-diskC are Ubuntu-server installs
>   - S1-diskA is the main server disk (sda)
>   - On S1, diskB is a copy of diskA - 'dd' is used initially, then
> regular rsync to maintain the copy.
>       (Initial dd is also done to diskD to setup partitioning.)
>
>   Backup server:
>   - S2-diskC is a basic install, but is used to regularly copy
> S1-diskB to S2-diskD
>       across the network.
>   - S2-diskD can be swapped for a spare drive to keep rolling system backups.
>
>   Scenarios
>   - Should the disk (diskA) fail in S1, then diskB can be swapped in
> and system rebooted.
>   - Should hardware in S1 fail, S2 can be moved in with diskA and
> system rebooted.
>
>   - These operations can be tested independently on S2 hardware.
>