# Use Chained Distributed Index Handler Servers

You can set up multiple DIH instances in a chained configuration. In this configuration, a parent DIH distributes to child DIH servers, which in turn distribute to child IDOL servers.

DIH system architecture (chained configuration)

In this configuration, the parent DIH forwards all IDOL Server index actions to the child DIH servers in the same way as to child IDOL Servers.

NOTE: Some index actions have different effects when sent to a child DIH than when sent to an IDOL Server, because the DIH forwards the action to multiple IDOL Servers.

Chaining provides an extra level of redundancy both at the DIH level and at the IDOL Server level. It also distributes network traffic and system load over a larger number of computers. Use a chained DIH server configuration to create a pool of IDOL Servers that are both fault-tolerant for maximum availability, and distributed for the best performance.

_FT_HTML5_bannerTitle.htm