Citrix: Configuring/Tuning Local Host Cache (LHC) time interval to query farm Data Store for missed changes

Local Host Cache

A subset of data store information, the local host cache, exists on each server in the farm, providing each member server with quick access to data store information. The local host cache also provides redundancy of the data store information, if for example, a server in the farm loses connectivity to the data store.

When a change is made to the farm’s data store, a notification to update the local host cache is sent to all the servers in the farm. However, it is possible that some servers will miss an update because of network problems. Member servers periodically query the data store to determine if changes were made since the server’s local host cache was last updated. If changes were made, the server requests the changed information.

Tuning Local Host Cache Synchronization

You can adjust the interval by which member servers query the farm's data store for missed changes. The default interval is 30 minutes. In most cases, this default setting is sufficient.

 

You can configure the interval by creating the following registry key on each server you want to adjust, with the value expressed in hexadecimal notation:

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Citrix\IMA\ DCNChangePollingInterval (DWORD)

Value: 0x1B7740 (default 1,800,000 milliseconds)

Note: This registry key is HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\IMA\ DCNChangePollingInterval (DWORD) on XenApp, 32-bit Edition.

 

You must restart the IMA Service for this setting to take effect.