Tuning your server

This topic discusses how to limit or increase the UnixWare resources available for NetWare Services. It also describes how to manage engines, configure shared memory size, limit error log file size, and set packet burst limits.

Managing engines

NetWare Services servers refer to certain processes as NCP engines. NCP engines are often considered the workhorses of NetWare Services servers and are responsible for initial processing of all client requests.

NetWare Services requires a minimum of two engines running at all times. The more work you require of your system, the more engines you will need to start.

Adding too many engines, however, may decrease performance. So generally, you need two engines per CPU.

Running more engines requires more RAM. (See ``Hardware requirements''.) After the NetWare server has booted, engines can be increased or decreased using the nwengine(1Mnws) utility. The number should be increased if the nxinfo(1Mnws) utility reports an excessive number of packets dropped because of server activity.

To prevent NetWare from using too many resources, you can limit the number of engines that can be started after boot time.

You can specify the number of NCP engines to start by using ``Number of NCP Engines to Start'' and ``Maximum Number of NCP Engines''. To specify how many engines to start automatically when the NetWare server process is started, see ``Tuning your server''.

Configuring shared memory

Shared memory is divided into pools and is controlled by internal locking mechanisms. Connections tables, data structures, trustee databases, NetWare server information, and volume table information are all data that shared memory uses.

If you use Packet Burst, add more connections, volumes, trustee assignments, and so on, you should increase the shared memory size.

See the ``Shared Memory Size'' variable in ``Tuning your server'' to configure shared memory.

Adjusting the size of your error log

Any errors your server experiences are saved to the error log file, SYS$LOG.ERR. You can change the size of this log depending upon how many messages you want to store in this file. Make sure you monitor this file because if messages come in and the file is full, messages are saved to a backup (SYS$LOG.OLD) and a new file, SYS$LOG.ERR, is created. Only one SYS$LOG.ERR.OLD is maintained.

See ``Error Log File Size'' in ``Tuning your server'' to change the size of your error log file.

Configuring packet burst

Packet Burst is a protocol built on top of IPX that speeds multiple-packet NCP reads and writes of files.

This protocol speeds the transfer of NCP data between a workstation and a NetWare server by eliminating the need to sequence and acknowledge each packet.

Packet Burst protocol is more efficient than the one-request/one-response protocol in earlier NetWare versions. With this protocol, the server or workstation can send a whole set (burst) of packets before it requires an acknowledgement.

By allowing multiple packets to be acknowledged, Packet Burst reduces network traffic.

It also monitors dropped packets and retransmits only the missing packets.

A client must negotiate the use of Packet Burst with a server before using it.

See ``Enable Packet Burst?'' and ``Packet Burst Buffer Size'' in ``Tuning your server'' to configure Packet Burst.

Tuning your server

Use the following procedure to tune your system.

The following list describes the prerequesites:

• Access to scoadmin(1M)

• System Owner permission to use scoadmin's NetWare Setup utility

1. From scoadmin, select NetWare, then select the NetWare Setup utility.

2. Select NetWare Server.

3. Select System Tunables.

   The ``System Tunables'' window appears.

4. Set the following variables as appropriate:

   • Basic. The Basic category shows the most commonly changed NetWare Services tunable variables:

     • Number of NCP Engines to Start. This variable specifies the number of NCP engines you want running as the default every time the NetWare server process starts. The default is 2. This is the minimum number that allows your system to run efficiently under normal conditions. We suggest that one NCP engine be set for every four clients that are active and not exceed four engines per CPU.

     • Maximum Number of NCP Engines. This variable specifies the maximum engines that can run simultaneously. The maximum default is 10. The maximum allowed is 50. This variable should always be greater than the ``Number of NCP Engines to Start'' variable.

     • Shared Memory Size. This variable specifies shared-memory segment size. This should be increased as the number of connections, trustee assignments, volumes, open files, and record locks increases.

     • Error Log File Size. This is the maximum size, in bytes, of the error log file, SYS$LOG.ERR. When the maximum size is reached, error log messages are copied to a backup and a new error log file is created. ``0'' means logging is not performed.

   • Advanced. The Advanced category shows and allows you to change the less frequently modified Packet Burst variables:

     • Enable Packet Burst? This variable controls whether the server allows clients to enable burst mode I/O. ``Yes'' means burst mode is enabled. ``No'' means burst mode is denied to all clients. The default is ``Yes''.

     • Packet Burst Buffer Size. This variable specifies the largest size burst the server can handle for a client. Changing this variable may require changing the shared memory size also.

Managing engines at the command line

You can use the nwengine(1Mnws) utility at the command line to start and stop engines while NetWare Services is running. To change the number of engines, type

nwengine number

Replace number with the new number of NCP engines you want running. The nwengine command determines the difference between the total number of NCP engines requested and those already running.

For example, if you have four NCP engines already running and you want to add three more engines, type the following command:

nwengine 7

Three more NCP engines will be started.

To reduce the number of NCP engines from seven to five (thus stopping two NCP engines), type

nwengine 5

You cannot decrease the number of engines below two. This is the minimum number of engines required to run NetWare Services.

Checking client connections using nxinfo

Use the nxinfo(1Mnws) command at the UnixWare command line to get a report on client connections. The report provides two pieces of information important to managing the number of engines you want active:

• The maximum number of clients ever active at one time. (If this number matches the number of licensed connections, you may need to buy more licenses.)

• The clients now active.

If a large number of packets is dropped because a server message indicates that the server is busy, you may need to add another engine. Adding too many engines, however, may decrease performance.