Re: [Handle-info] redundancy questions

[Sean Reilly <sreilly@cnri.reston.va.us>]

Hi Michael,

On Nov 27, 2007, at 9:10 PM, Michael Della Bitta wrote:
> Hi, I just have a few quick questions on handle server redundancy:
>
> We're investigating running two instances of the handle server on  
> separate machines, both of which would be reading from the same  
> Oracle schema.
>
> 1. Is there a proven way to hide both the proxy servers behind a  
> load balancer so they have the same URL?

The URL for the handle server process shouldn't be significant and I  
would advise against directly addressing the handle server's HTTP  
interface for any reason other than testing/debugging.  The handle  
server is contacted by handle clients using its IP address (not domain/ 
host name) primarily using the native handle protocol over port 2641  
(UDP and TCP with a fallback to HTTP).

The handle protocol has built-in load balancing/failover support so if  
you provide the contact information for both servers (their  
siteinfo.bin files) to hdladmin@cnri.reston.va.us they can both be  
listed as contact points for your prefix(es).

> 2. If the main server dies or needs to go offline, do handle  
> administration requests somehow fail over to the secondary server?

If both server's "siteinfo.bin" files are registered for your prefix  
then handle clients will talk to either or both servers when doing  
resolution.  If both of your servers were set up as "primary" servers  
then that will be indicated within the siteinfo data and clients can  
talk to either server to do administration.

However, you should consider the mirroring system before deciding to  
have two primary handle servers.  If at some point you add another  
handle server and wish to use handle mirroring (as opposed to  
mirroring within Oracle) to keep it up to date then you should ask hdladmin@cnri.reston.va.us 
 to turn off the primary flag for one of the servers so that clients  
only go to one of the servers for administration.  This will allow any  
new secondary servers to retrieve the incremental changes from the  
single primary server.

Thanks,
Sean



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