Exchange 2000 Enterprise Server support on Windows 2000 Datacenter Server

This article describes best practices for deploying Exchange 2000 Enterprise Server on a computer that is running Windows 2000 Datacenter Server. Exchange 2000 Enterprise Server Service Pack 1 (SP1) or later is an officially certified Windows 2000 Datacenter Server program. This certification ensures that Exchange 2000 Enterprise Server SP1 is reliable and stable on the Windows 2000 Datacenter Server operating system. For additional information about Exchange 2000 Enterprise Server SP1 and Windows 2000 Datacenter Server program certification, see the following VeriTest Web site: Microsoft provides third-party contact information to help you find technical support. This contact information may change without notice. Microsoft does not guarantee the accuracy of this third-party contact information.

This article focuses primarily on Exchange 2000 Enterprise Server support for the processor and memory scalability features of Windows 2000 Datacenter Server. The four-node clustering feature that is enabled with Windows 2000 Datacenter Server is described in the "Deploying Microsoft Exchange 2000 Server Service Pack 1 Clusters" white paper. For additional information, see the following Microsoft Web site: This document assumes a high level of knowledge in the areas of Windows 2000 Datacenter Server and Exchange 2000 deployment and administration. The intended audience is professional system engineers and administrators who are designing an Exchange 2000 Enterprise Server deployment based on Windows 2000 Datacenter Server.

Exchange 2000 Support of Windows 2000 Datacenter Server

What Versions of Exchange 2000 Are Supported with Windows 2000 Datacenter Server?

The following version of Exchange 2000 are supported with Windows 2000 Datacenter Server:

• Exchange 2000 Enterprise Server with Exchange 2000 SP1 or later

The following versions of Exchange 2000 are not supported on Windows 2000 Datacenter Server:

• Exchange 2000 Enterprise Server (RTM version)
• Exchange 2000 Standard Server (RTM version)
• Exchange 2000 Standard Server with Exchange 2000 SP1 or later

As with any Windows 2000 Datacenter Server solution, the hardware must also be certified. Because of the many design considerations in Exchange 2000, Exchange 2000 Enterprise Server does not fully take advantage of some of the features that Windows 2000 Datacenter Server offers.

Multiple Processor Support

Windows 2000 Datacenter Server supports 32 processors on a single server. Exchange 2000 SP1 mailbox servers only scale well to 8 processors on a server. Partition 32-processor computers into four 8-processor servers by using hardware partitioning. If you are running Exchange 2000 SP1 on servers that have more than 8 processors, you are using processor resources inefficiently; avoid that situation. Exchange 2000 is a distributed program and is designed to scale out very effectively. For additional information about how to size processor resources, see the following resources:

• The "Microsoft Exchange 2000 Front-End Server and SMTP Gateway Hardware Scalability Guide" white paper, which is available at the following Microsoft Web site:
  http://www.microsoft.com/technet/prodtechnol/exchange/2000/library/efessghs.mspx (http://www.microsoft.com/technet/prodtechnol/exchange/2000/library/efessghs.mspx)
• The "Microsoft Exchange 2000 Server Back-End Mailbox Scalability" white paper, which is available at the following Microsoft Web site:
  http://www.microsoft.com/technet/prodtechnol/exchange/2000/library/e2ksbems.mspx (http://www.microsoft.com/technet/prodtechnol/exchange/2000/library/e2ksbems.mspx)

Process Settings

Windows 2000 Datacenter Server includes a Process Control feature that server administrators can use to limit the amount of memory that individual processes consume and configure processor affinity on a per-process basis.

Memory

On Windows 2000 Datacenter Servers-based computers that are running programs other than Exchange 2000, limit the Exchange 2000 information store working set by using Process Control. Because the /3GB flag is not likely to be set in the Boot.ini file when other programs (such as Microsoft SQL Server 2000) are running on a Windows 2000 Datacenter Server-based computer, a working set limit of 600 megabytes (MBs) helps ensure that the information store’s 2-gigabyte (GB) virtual address space allocation is not exceeded.

Processor

You can extend Exchange 2000 multiple-processor scalability by setting processor affinity. In a sample test, the following results were obtained:

• Majority Post Office Protocol version 3 (POP3)/Simple Mail Transfer Protocol (SMTP) mix, with 10 percent load provided by MAPI
• 8 processors total (550 megahertz [MHz] Xeon 1 MB L2 Cache)
• 3x550 MHz processor set for the inetinfo process
• 5x550 MHz processor set for the store process
• Results: 67 percent processor usage with 14,950 context switches per second
• Results with no affinity set: 69 percent processor usage with 16,098 context switches per second

If you set affinity, both context switching and CPU usage decrease.

32 Gigabyte Memory Support

Another prominent Windows 2000 Datacenter Server feature is support for up to 32 GB of RAM. Programs can support this much memory by using one or a combination of the following methods. Exchange 2000 does not use memory beyond 4 GB on a server efficiently; you should not configure Exchange 2000 servers with more than 4 GB of memory.

Per-Process Memory Limitations

By default, Windows 2000 reserves 2 GB of virtual address space for the kernel and 2 GB of virtual address space for every different process that is running on the computer. This limits each process from using more than 2 GB of memory. If the /3GB flag is added to the Boot.ini file, Windows 2000 reserves only 1 GB for the kernel, which provides 3 GB of virtual address space for each process. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Instancing

Instancing refers to the ability to run multiple instances of a program as separate processes on the same computer (for example, running multiple copies of Microsoft Notepad). Each process is limited to either 2 or 3 GB of virtual address space (depending on use of the /3GB Boot.ini flag as described above). If you use instancing, you allow the program to use more than 3 GB of a server’s memory resources. If you have four instances of Inetinfo.exe, you have the potential to use 4 times 3 GB of memory (12 GB).

Exchange 2000 SP1 does not support instancing.

Physical Address Extension/AWE

Windows 2000 Datacenter Server extends the Physical Address Extension (PAE) feature of Windows 2000 Advanced Server to 32 GB. This enables programs that were written to this API to make use of up to 32 GB of physical memory. Placing /PAE in the Boot.ini file enables Windows 2000 to use memory beyond 4 GB. Exchange 2000 does not make use of this application programming interface (API) and receives very little performance benefit on Windows 2000 Datacenter Server-based computers that are enabled for PAE. On servers with more than 16 GB of memory, PAE must reserve more kernel memory space so that the /3GB switch cannot be used. If the /3GB switch and the /PAE switch are used in tandem on a computer with 32 GB of memory, PAE is able to access only the first 16 GB (this information is displayed in Windows 2000 Task Manager). If you remove the /3GB flag from the Boot.ini file, you can access all 32 GB of memory (with a program that is written to the AWE API), but this might cause problems for Exchange 2000. Depending on the number of storage groups or Messaging Databases (MDBs) that are configured for an Exchange 2000 server, Exchange may run out of virtual address space. The more storage groups or MDBs that are configured on a server, the more virtual address space is consumed. More specifically, Exchange 2000 may run out of virtual address space on a server that has more than 1 GB of physical RAM and does not have the /3GB flag set in the Boot.ini file. If you place /PAE in the Boot.ini file, you enable Windows 2000 to use memory beyond 8 GB. AWE is the API that is exposed when this switch is enabled. Programs that make use of this API can allocate memory beyond 8 GB, up to 32 GB.

Memory Usage Summary

Exchange 2000 servers work well with the /3GB switch (and its use is required on servers with more than 1 GB of physical memory), but Exchange 2000 does not support instancing or PAE and AWE. This limits an Exchange 2000 server to about 4 GB of usable memory. Installing more than 4 GB of physical memory on an Exchange 2000 SP1 server is not recommended.

Example Exchange 2000 Enterprise Server SP1 and Windows 2000 Datacenter Server Configurations

With Exchange 2000 Enterprise Server SP1 running on a 32-processor server:

• 32-processor Windows 2000 Datacenter Server
• 16 GB of RAM

Configuration: partition the server into four hardware partitions. Make each hardware partition of eight processors and 4 GB of memory. Include the /3gb switch in each of the hardware partitions' Boot.ini files.

With Exchange 2000 Enterprise Server SP1 running on a 32-processor server with another Windows 2000 Datacenter Server-certified program, such as Microsoft SQL Server 2000 (multiple hardware partitions):

• 32-processor Windows 2000 Datacenter Server
• 32 GB of RAM

Configuration: partition the server into two hardware partitions. The first hardware partition, to be used for Exchange 2000, should be made up of eight processors and 4 GB of memory. The second hardware partition, which is used for SQL Server 2000, should be made up of 24 processors and configured with 24 GB of RAM. Include the /3gb switch in the Exchange 2000 hardware partition’s Boot.ini file and include the /PAE switch in the SQL Server 2000 hardware partition’s Boot.ini file.

NOTE: This is the recommended method for combining Exchange 2000 with other Windows 2000 Server Datacenter Server programs on a single hardware platform.

With Exchange 2000 Enterprise Server SP1 running on a 32-processor server with another Windows 2000 Datacenter Server-certified program such as SQL Server 2000 (single hardware partition, not recommended):

• 32 processor Windows 2000 Datacenter Server
• 32 GB of RAM

Configuration: partition the server into a single hardware partition that is made up of 32 processors and 32 GB of RAM. Include the /PAE switch in the hardware partition’s Boot.ini file. By not including the /3gb switch, you limit the Exchange 2000 information store to 2 GB of virtual address space. You must exclude the /3gb switch to enable the server to see more than 16 GB of RAM.

Process Control Settings

Note the following information about process control settings

• Configure the following Exchange 2000 processes to use only the first four to eight processors:
  • Exchange 2000 information store (Store.exe)
  • Internet Information service (Inetinfo.exe)
  • Exchange 2000 System Attendant (Mad.exe)
  • Exchange 2000 message transfer agent (Emsmta.exe)
• Configure the Exchange 2000 information store (Store.exe) process to be able to use only 1 GB of working set.
• The Exchange 2000 configuration in this mixed scenario (virtual address space) benefits from using fewer database storage groups (one storage group is recommended for this configuration).
• Configure SQL Server 2000 to use only the remaining 24 or 28 processors and 30 GB of memory.

NOTE: This is not a recommended method for combining Exchange 2000 with other Windows 2000 Datacenter Server programs on a single hardware platform. Exchange 2000 is less efficient in this scenario. It is recommended that you place Exchange 2000 on a separate hardware partition than other Windows 2000 Datacenter Server programs.

For additional information, visit the following Microsoft Exchange 2000 Server Web site: For more information about the Datacenter program and other BackOffice programs, click the following article numbers to view the articles in the Microsoft Knowledge Base: