Re: Mirror applications on Linux Server

[Miles Fidelman <mfidelman@meetinghouse.net>]

lrhorer wrote:
> > > > I am building an application which needs to have high reliability.
> > > > I have two essentially identical Linux servers which can host the
> > > > application.  Right now, I have the programs - a bash script and a c
> > > > binary, running on one machine every minute in a cron job.  I also
> > > > have an rsync cron job running to synchronize the files on the
> > > > standby machine so the data (and binaries, of course) will be identical.
> Thanks.  I skimmed the intro, and I'm not sure heartbeat is really what
> I need.  These aren't server applications that run full-time on the
> machine.  They are relatively simple programs that only take a few
> seconds to run, and then terminate (hopefully with a return value of
> 0), to be run again in 60 seconds.  I don't need the inter-machine
> service to cause something to happen on the standby system if the apps
> are no longer running, or at least not immediately so.  Rather, I need
> the standby machine to take over if:
>    
This might work:

1. Use DRBD to keep your disks (or specific volumes) in sync.  Run it in 
it's standard primary-secondary mode.

2. Run the job on both machines.  When it starts, have it check whether 
the volume is in primary or secondary mode; if in secondary mode, abort.

Of course that only works if your backup machine doesn't need to access 
the disk volume for other things.



--
In theory, there is no difference between theory and practice.
In<fnord>  practice, there is.   .... Yogi Berra