IBM TotalStorage DS6000 Series: Performance Monitoring and Tuning

Chapter 9. Open system servers - Windows 311

Ideally, the paging device will be a separate physical drive. Having data that is being

accessed on the same drive as the paging drive can reduce performance, especially when

multiple logical drives are configured on one physical drive. This causes long seek operations

and slows performance.

If the page files and active data must reside on the same physical device, place them on the

same logical drive. This will keep the page file and data files physically close together, and will

improve performance by reducing the time spent seeking between the two logical drives. Of

course, you can ignore this issue if no I/O access is made to the data drive during normal

operation.

9.2.3 File system cache tuning

In Windows Server 2003 and 2000, you can optimize server performance by tuning the file

system cache.

The file system cache is a dynamic memory pool used to store recently accessed data for all

cacheable peripheral devices, which includes data transfers between hard drives, networks

cards, and networks. The Windows Virtual Memory Manager copies data to and from the file

system cache as though it were an array in memory. When data resides in file system cache,

it will improve performance and reduce disk activity.

Two applets of Windows Server 2003 determine how much system memory is available to be

allocated to the working set of file system cache versus how much memory is available to be

allocated to the working set of applications, and the priority with which they are managed

against one another.

Settings in these options should be set according to the server role.

The two options are:

򐂰 File and Printer Sharing for Microsoft Networks (Network Control Panel applet), relates to

a server’s network performance. It decides how the server allocates memory to local

applications versus network connections. It affects not only network but also disk

performance.The most important memory allocation controlled by this setting is that given

to the system cache. It controls how a server prioritizes its memory allocations and thread

priorities for network services versus local applications and the size given to the system

cache.

򐂰 System (System Control Panel applet), also referred to in Microsoft documentation as

Performance Options, as it has consolidated several performance applets into one

location.

To change File and Printer Sharing for Microsoft Network setting (Both Windows Server 2003

and Windows 2000),

1. Click Start -> Settings -> Network and Dial-Up Connection.

Note: When configuring SAN Boot, it is recommend to put it on local physical disk for

paging for same reason. But if there is no page file on boot partition (usually C:\Windows or

C:\WINNT), system dump (memory.dump) is not created when STOP event (blue screen)

occurs.

Tip: Windows Server 2003 has two applets to manage file system cache as compared with

the previous version of Windows which has just one applet.

312 IBM TotalStorage DS6000 Series: Performance Monitoring and Tuning

2. Select any of your local area connections (it does not matter which one).

3. Click File -> Properties.

4. Select File and Print Sharing for Microsoft Networks.

5. Click Properties. The window shown in Figure 9-3 will appear.

Figure 9-3 Configuring the system cache in Windows 2000

The file system cache has a working set of memory like any other process. The option chosen

in this dialog effectively determines how large the working set is allowed to grow to and with

what priority the file system cache is treated by the operating system relative to other

applications and processes running on the server.

You have four choices but typically only one of the bottom two options is selected for an

enterprise server implementation:

1. Minimize memory used.

This choice will minimize the memory used for disk cache and maximize the memory

available for the operating system. However, on file servers, the resulting performance

would not be desirable. Therefore, only use this choice for workstations.

Note: This setting affects all LAN connections, so which LAN connection you choose in the

above steps is not important. If you are not using this system as a file system server, then

you will not be able to modify the cache priorities here.

Better for file servers and

servers with large amount of

RAM

Better for application

servers and those

with internal memory

management features