topic Re: DNS Config in Operating System - HP-UX

DNS Config

majid64 — Tue, 10 Mar 2009 04:09:52 GMT

Hi,

i have two ftp server (on local) with same data on both and naturally different IP address,
how to config dns server when a client send domain for resolve on dns server, dns server look at two ftp server which has lesser busy resolve to that ftp server ip?

thanks

Re: DNS Config

Avinash20 — Tue, 10 Mar 2009 04:17:27 GMT

I am not sure, if DNS is used to have load-balancing which you have specified above.

DNS is only used for name resolution.(forward and reverse)

Re: DNS Config

majid64 — Tue, 10 Mar 2009 04:20:50 GMT

i'm sure about it,it's possible but i don't know how do it.

Re: DNS Config

Matti_Kurkela — Tue, 10 Mar 2009 08:08:45 GMT

Our old OpenVMS cluster used to have this kind of load balancing scheme.

To achieve that using DNS, you must have a separate program that measures the load of the both servers and continuously updates the DNS records to point to the less busy server.

You cannot do this with a standard DNS server alone: the standard HP-UX DNS server software (BIND) does not include the functionality for looking into other servers' load levels.

With proper DNS tuning (low TTL values), this may be suitable for local load-balancing, but if your servers are accessed world-wide, the propagation delays between the caching DNS servers may make this solution too slow to react to sudden load spikes. Even in the local use, you must accept that some requests will always arrive to the busier server: you'll never get a "perfect" distribution of load.

MK

Re: DNS Config

rick jones — Tue, 10 Mar 2009 23:25:13 GMT

So, apart from putting a load balancing appliance (or system with appliance software on it) in front of the two FTP servers, your best bet is going to be DNS round-robin rotating through the IPs on each query for the name.