Optimizing the smoothing index

The smoothing index limits the amount that a server’s weight can change, effectively smoothing the change in the distribution of requests.

About this task

The manager calculates the server weights dynamically. As a result, an updated weight can be very different from the previous one. Under most circumstances, this will not be a problem. Occasionally, however, it may cause an oscillating effect in the way the requests are load balanced. For example, one server can end up receiving most of the requests due to a high weight. The manager will see that the server has a high number of active connections and that the server is responding slowly. It will then shift the weight over to the free servers and the same effect will occur there too, creating an inefficient use of resources.

To alleviate this problem, the manager uses a smoothing index. A higher smoothing index will cause the server weights to change less drastically. A lower index will cause the server weights to change more drastically. The default value for the smoothing index is 1.5. At 1.5, the server weights can be rather dynamic. An index of 4 or 5 will cause the weights to be more stable.

Note: In most cases, you will not need to change this value.

Procedure

Set the smoothing index, in seconds. For example, to set the smoothing index to 4 enter the following command:
dscontrol manager smoothing 4
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Last updated: May 14, 2012 02:14 PM EDT
File name: tprf_optsmooth.html