4.6 Load balancing

If your rr table contains more than one address record for the same name, and one or more of the records has an aux value greater than zero, MyDNS will weight its response using the value in aux.

MyDNS uses the value in aux to determine the order in which addresses are listed. Clients usually start with the first address and work their way down, so addresses that are usually listed first will bear the heaviest client load.

A low value in aux makes an address record more likely to be listed first. The balancing algorithm causes servers with a lower aux to be selected more frequently than those with higher values, although all servers will still be listed first occasionally, as the algorithm is partially random.

Records where aux is 0 (zero) will be listed first almost every time. Records where aux is 50,000 or greater will always be listed last.

Here's an example of how hosts were distributed on a 100,000 query test against ten hosts with aux values 10-100. The number shown is the number of times that host was listed first:

aux 10 51,211 aux 20 21,881 aux 30 10.983 aux 40 6,209 aux 50 3,661 aux 60 2,311 aux 70 1,526 aux 80 1,032 aux 90 675 aux 100 511