[hobbit] Backup server for HOBBIT

[Henrik Stoerner]

On Mon, Jan 16, 2006 at 12:38:09PM -0700, Winn Beutler wrote:
> 
> I have searched the HOBBIT archive but cannot find anything on setting up 
> a hot standby HOBBIT server that receives input from the clients along 
> with the primary server but does not send out alerts unless the primary 
> server goes down.  Any howto's on this?

I don't think a *hot* standby has been discussed much.

It should be fairly simple. On the standby server, you just disable the
[bbpage] task (running hobbitd_alert) until the primary server is down.
When that occurs, change the hobbitlaunch.cfg file to have the bbpage
task enabled, and alerts will start to flow.

The trick of course is to detect when the primary server is down; 
how you do that depends on the setup you have. If there is some
sort of clustering software installed it might be very simple;
if not, you'll have to rely on some sort of connectivity between
the two hosts and their checking of each other.

The only problem I see is that when the backup server starts the
hobbitd_alert module, it will see all alerts as being "new", so
there might be an initial burst of alerts because all of the info 
about when to repeat an alert is lost. If you can share the
~hobbit/server/tmp/ directory between the servers (e.g. it is on a
SAN storage) then that will not happen, because the backup server
will pickup the checkpoint files that stores this information
across restarts of Hobbit.


Regards,
Henrik