How to: Modify the size of your Windows Server 2008 R2 based DHCP server’s JET database page cache at runtime

You may want to consider modifying the JET database page cache size of your Windows Server 2008 R2 based DHCP server to take advantage of these possible benefits:

·         Increasing the cache size improves active queue length, ACK/sec, and disk reads per second.

·         All requesting clients should get addresses relatively quicker as a result of significant improvements in DHCP transactions. The server should respond to all V4 & V6 requests without keeping them long in the active queue.

You can change the size of your JET database page cache at runtime by modifying the JET_paramCacheSizeMax and JET_parmCacheSizeMin parameters of the Extensible Storage Engine (ESE). Typically, the cache automatically tunes its size as a function of database and server activity levels. If the JET_paramCacheSizeMax parameter is set to a value less than 2 MB, JET_paramCacheSizeMax will default to 2 MB as the upper bounds of the cache size. If it is set to a value greater than 2 MB the cache will adjust up to that size in database pages. JET_paramCacheSizeMax will not remain static at any upper bound value higher than 2 MB.  Follow this procedure to configure the JET_paramCacheSizeMax parameter on your DHCP Server:


Configure the JET_paramCacheSizeMax parameter

1.   Create or modify the registry key (DWORD) JetDatabaseMaxCacheSize at HKLM\SYSTEM\CurrentControlSet\Services\DhcpServer\Parameters\. The default value is 2 MB.  If the value is less than 2 MB, JETDatabaseMaxCacheSize will default to 2 MB.  

2.   Restart the DHCP Server service.


Corey Plett
Technical Writer
The Windows Server Networking Documentation Team

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