# Round Robin Mode Configuration Parameters

When Round Robin mode indexing is enabled, you must configure the `[RoundRobinMode]` section.

Use the `[DAHServerN]` options to configure child servers for power up and shut down when Round Robin roll-over occurs, to optimize both query handling and data indexing across a group of child servers.

For example, you can disable queries to today’s server. Indexing speed for today’s server is optimal because it is not being queried. Query handling speed for the other days’ servers is optimal because they are not indexing data. Today’s server has a period to index data before it is queried again through the DAH.

For example:

    [Server]
    Port=16000
    DIHPort=16001
    DateFormatCSVs=SHORTMONTH#SD+#SYYYY,DD/MM/YYYY,YYYY/MM/DD,YYYY-MM-DD,EPOCHSECONDS
    RoundRobinMode=TRUE

    [DistributionIDOLServers]
    Number=3

    [IDOLServer0]
    Host=localhost
    Port=6502

    [IDOLServer1]
    Host=localhost
    Port=6602

    [IDOLServer2]
    Host=localhost
    Port=6702

    [RoundRobinMode]
    ServerImmediateStart=2
    NextServerStartTime=00:00
    NextServerStartDate=2006/10/20
    PeriodInSec=86400
    RoundRobinMode=TRUE

    [DAHServer0]
    Host=thisisahost
    Port=12000
    ShutDownEnginePeriods=0,-1

    [DAHServer1]
    Host=thisisanotherhost
    Port=13000
    StartUpEnginePeriods=-2

In this example, the Distributed Index Handler immediately starts sending index data into IDOL server 2. The Distributed Index Handler switches to forward data to the next server, IDOL server 0, on 20 Oct. 2006 at 00:00, after which it indexes into each child server for 1 day before a roll over to a different child server takes place. When a roll over occurs, the DAH child server that indexed data yesterday and the DAH child server that indexes data today shut down. At the same time, the DAH child server that indexed data the day before yesterday are powered up.

NextServerStartDate | PeriodInSec | ServerImmediateStart
NextServerStartTime | RespectDocumentDate | DAHServerN Configuration
PeriodInDay | SendInitialOnRollover |

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