Optimizing DHCP Server Performance
Updated: March 28, 2003
Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2
You can optimize the performance of DHCP servers in your organization by doing the following:
Extending the duration of the IP address lease.
Improving DHCP server hardware, specifically upgrading to a faster hard drive or adding random access memory (RAM).
Extending the IP Address Lease and Renewal Duration
The volume of traffic on your network can have a negative impact on DHCP performance. For example, a subnet that relies on a DHCP server at a remote location on the WAN might experience poor performance at start of day, when users turn on computers and a large load of requests might be sent over the network.
DHCP traffic does not use significant network bandwidth during periods of normal usage; however, the following two phases of DHCP client configuration generate some network traffic load:
IP address lease
IP address renewal
When a DHCP client initializes TCP/IP or renews its address lease, it acquires an IP address from the DHCP server. This process results in an exchange between the DHCP client and the DHCP server, which typically consists of four packets, each containing a maximum of 4 kilobytes (KBs). For more information about the DHCP exchange, see the Networking Collection of the Windows Server 2003 Technical Reference (or see the Networking Collection on the Web at http://www.microsoft.com/reskit).
You can reduce the amount of network traffic generated by DHCP IP address lease and IP address renewal by extending the lease duration. Before you extend the lease duration, you must take into consideration other factors in your network, such as ratio of clients to available IP addresses, or clients that frequently lease addresses on more than one subnet, such as laptops that move frequently. If you have a relatively stable network and many more available IP addresses than DHCP clients, increasing the lease duration reduces network traffic, because DHCP messages are sent less frequently. If, however, you have a limited number of IP addresses available to your DHCP clients, or a network that changes frequently, a longer lease duration might cause you to run out of IP addresses because IP addresses are not returned to the address pool and made available to other DHCP clients until the lease expires. For more information about extending the lease duration, see "Determining Lease Duration" later in this chapter.
Improving DHCP Server Hardware
You can optimize DHCP performance in your system by optimizing individual DHCP server performance. Windows Server 2003 includes performance monitoring tools that you can use to test and monitor your servers.
For more information about performance monitoring tools, see "Performance Monitoring Tools" in Help and Support Center for Windows Server 2003.
The primary factors that impact DHCP server performance include:
The speed of the server disk drives.
The amount of RAM installed in the DHCP server computer.
The greatest volume of disk usage occurs when the service is started and when the database is backed up. When planning your DHCP server hardware specifications, evaluate the average time required for disk access and for disk read/write operations. If necessary, maximize DHCP server performance by increasing RAM and purchasing high-speed disk drives for the servers.