Re: Annex E, GLADE and fault-tolerance

[fjloma@andaluciajunta.es (Francisco Javier Loma Daza)]

"Dr. Adrian Wrigley" <amtw@linuxchip.demon.co.uk.uk.uk.uk> wrote in message news:<%mK2b.4892$L15.72@newsfep4-winn.server.ntli.net>...
> Hi all!
> 
> OK.  So I've got my client/server application working now, but have a problem
> with fault tolerance. (I am using Annex E/GNAT 3.15/GLADE/Linux)
> 
> My objective is for clients to be able to run continuously for months at a time.
> I also want the server to run for months too.  If a client terminates, I want
> to be able to restart it.  If the server terminates, I want to be able to
> restart it too.
> 
> So I use the "Reconnection" and "Termination" policy so that I can restart the
> client or the server as necessary.  If the main boot server is separate from
> the client and application server partition, it works fine.  Except when the
> main boot server is restarted :(
> 
> When the main boot server is terminated and restarted, executing clients run into
> problems.  The existing clients cannot communicate with the new main boot
> server invocation, nor with partitions started after the new main server is started.
> 
> The effect is that if the main boot server dies, all the clients need to be
> restarted too. I have read the GLADE Users' Guide carefully, and can't see a
> solution to the problem - it seems to be a design feature(!)
> 
> How can I prevent failure of the server causing failure of all the clients too?
> 
> I just want the "simple" behaviour like web servers and clients, where you don't
> need to restart all the clients each time a server reboots.
> 
> Thanks for any help on this!

Can you make a trivial passive partition on which install the boot
server? as this partition will not contains any code, can be assumed
that it will not die unexpectly, but if you don't feel good, you can
make another (the real server for example) a boot mirror with the
boot_mirror command line option. The real server can be another
partition that can be terminated alone, leaving the passive boot
partition running.
I have no time for test but I hope that helps