# Distribution

You can distribute IDOL Server over multiple machines, by using the Distributed Index Handler (DIH) and Distributed Action Handler (DAH). These components distribute index actions and ACI actions respectively to multiple IDOL Servers.

## Distributed Index Handler

The Distributed Index Handler (DIH) distributes index actions between multiple IDOL Servers or Content components.

DIH can either index all documents into multiple child servers, or it can distribute the documents evenly between them. Multiple identical copies of child servers allows load balancing and failover, while distributing the index allows you to store more content.

## Distributed Action Handler

The DAH distributes actions between IDOL Servers, or components.

The most common use of DAH is to distribute queries to multiple Content components or IDOL Server. In this case, DAH can either distribute between identical IDOL Servers, for load balancing and failover, or it can distribute and combine results from multiple IDOL Servers that each contain a part of the whole index.

You can also use DAH to distribute actions between multiple copies of any ACI server. In this case, it can balance load over servers to allow you to scale your system.

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