[Date Prev][Date Next] [Chronological] [Thread] [Top]

RE: achieve server redundancy



> -----Original Message-----
> From: owner-openldap-software@OpenLDAP.org
> [mailto:owner-openldap-software@OpenLDAP.org]On Behalf Of
Kent_Wu@trendmicro.com

> Round robin sounds good however it still hasn't solved my real issue.
> What I want to achieve is failure-recovery, through Round 
> Robin I can achieve
> a bit load balance however when one server is down, the 
> client who happens to be RR'ed to query that server 
> is going to get an error response still. It seems the load 
> balancing switch might be a good choice since it would 
> probably try to detect the status of those servers.

Yes, go with the load-balancer.

> 	I know windows domain controller works this issue out 
> with DNS pretty well, it would periodically update its 
> records in the DNS and the client actually queries the DNS to 
> get the list of healthy servers before really contacting the 
> server. I don't think this approach is available for openLDAP 
> server and other platforms however I might be wrong.

The same can be accomplished with DNS if you have a monitoring mechanism that
detects when servers have died; it just needs to use dynamic DNS update to
rewrite the list of A records for the round-robin hostname. But using DNS
this way is an ugly solution; it also fails if the client machine does its
own hostname caching.

Go with a purpose-built load-balancer. Use the right tool for the job.

  -- Howard Chu
  Chief Architect, Symas Corp.       Director, Highland Sun
  http://www.symas.com               http://highlandsun.com/hyc
  Symas: Premier OpenSource Development and Support 

<<attachment: winmail.dat>>