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TITLE: How To Configure a NetWare Lite Server
DOCUMENT ID#: FYI.P.6060
DATE: 04Dec92
PRODUCT: NetWare Lite
PRODUCT VERSION: All versions
SUPERSEDES: NA
SYMPTOM: NA
ISSUE/PROBLEM
How to Configure a NetWare Lite Server
The purpose of this document is to explain the server statistics that are configurable within NetWare Lite. These Server statistics can be viewed and changed in the Net utility. To access the configuration menus, do the following steps:
From the c:> prompt type "net"
select Supervise the Network
select Server Configuration to change settings
select Server Status to view settings
SERVER CONFIGURATION SCREEN
The following is an example of the server configuration screen with default settings:
Configuration Information for Server NWLITE
CFG FUTURE
Connections (2-25) 4 4
Client tasks (4-200) 10 10
Network directories (2-20) 4 4
Network printers (0-5) 1 1
Print buffer size (256-4096) 512 512
Number of receive buffers (3-20) 6 6
Receive buffer size (512-4096) 1024 1024
Number of read buffers (2-20) 3 3
Read buffer size (512-4096) 1024 1024
Allow remote management (Y/N) Y Y
Future server name: NWLITE
CFG and FUTURE Columns
There are two columns of statistics on the right hand side of this table labeled CFG and FUTURE. The CFG column indicates the settings that are currently being used. The FUTURE column is used to determine the network settings to be implemented the next time the network is started. If you want to make a change, make it in the FUTURE column and then reboot the machine. Once the machine is re-booted, the new settings will be in effect and will appear in the CFG column.
Configuration Settings
Each item in the menu will be discussed in some detail. After each item is described, configuration information will be given to help correctly configure each item.
CONNECTIONS
Every computer on the network (client or server or both) has a connection table. This table keeps track of the number of connections that the computer has with other computers. This table is not able to be viewed by a user, however, the number of connections can be limited on a server. A connection is established when one computer accesses another computer across the network. For example, a connection is established if a client accesses a network resource, such as a network directory or network printer, located on a server.
Server Connection Table
A server's connection table actually contains a list of the node addresses of every client computer accessing printers or network directories on that server. Because the connection is actually the node address of the network card, only one connection is established per machine, regardless of how many drives a computer has mapped or how many printers a client machine is captured to. It is not possible for the number of connections in the server connection table to be greater than the total number of clients on the network. When a server receives a request to map a drive, for example, it will look down the list of existing connections and will create a new connection only if the address of the requesting computer is not already on the list.
Temporary Connections
Temporary connections are occasionally established by the net utility to modify a user account, change a server's configuration, etc. After the net utility has finished using the temporary connection, the connection is cancelled.
Setting Connections
Set the number of connections for each server by considering how many clients might be mapped or captured to the server at one time and add one to that number to provide for any temporary connections. Each connection in the Server's configuration menu uses approximately 80 bytes of memory.
CLIENT TASKS
Client tasks are the number of programs permitted to open files on a server. Each time a program on a client uses a resource on a server (i.e. starting a program), one client task is registered in a table on the server. This is the case whether the client loads the program from the server or whether it loads it from its own hard drive. If the same program opens more than one file, only one client task is still registered, because client tasks refer to the number of programs that are opening files, not the number of files that are open on the server. On the other hand, if two different programs on a client open files on a server, then two client tasks are recorded in the table. Some programs call other programs which use server resources. When this happens, client tasks will increase by more than one when the program is initially started.
There are a variety of problems associated with not having enough client tasks. Usually errors will be displayed by the application that is currently running. Occasionally, the whole network will hang.
Client Task Configuration Information
The number of client tasks defaults to 10. A good rule of thumb is to set the number of client tasks to 10 per machine connected to the server (i.e. If five machines have drives mapped to a server, set the client tasks on the server to 50). This should provide enough client tasks to operate the network. Approximately 100 bytes of memory are reserved on a server per each client task.
Check the server status screen frequently to verify that you have enough client tasks. If you see the "peak" number of tasks in the server status screen approaching the CFG number (within 6) you should increase the number of client tasks to avoid problems. The CFG number should always be at least six higher than the PEAK number.
Proper configuration of the number of client tasks on a server is especially important under the following conditions: 1- Running Microsoft Windows. 2- Using a disk intensive program (i.e. a database program). 3- Supporting many clients.
Network Directories
A network directory is a directory on a server that can be accessed by clients on the network. Increasing the number of network directories on a server, simply allows more of its directories to be accessed by users across the network.
Network Directory Configuration Information
Set the number of network directories to as many as needed (up to 20).
Network Printers
This figure designates the maximum number of network printers allowed on a server. NetWare Lite will support up to 3 printers per server. A printer on a server does not necessarily have to be designated as a network resource. It can be run locally if SERVER.EXE is not loaded into memory. Each network printer defined takes up approximately 884 bytes of memory on the server.
Network Printer Configuration
This number should correspond to the number of printers physically connected to the server and defined as network resources. The maximum number of network printers per server is three.
Print Buffer
Print Buffer Size
NetWare Lite uses a print buffer to temporarily store information before it is printed. A print job follows the following path to the printer:
Application --- DOS --- Client --- || network ||--- Server --- Printer
When someone prints a job from a client machine to a network printer, the information first goes to DOS. After realizing that the printer port (lpt1 for example) has been captured to a network printer, DOS sends the print job to the network software on the client machine. The print job is sent across the network cabling to the computer with the printer attached and then taken by the server software and spooled to a directory on the hard drive. The path to where the data is being spooled is C:\NWLITE\NLCNTL \SLPT1. The NLCNTL subdirectory is a hidden directory and the SLPT1 directory corresponds to the printer port captured on LPT1. (If LPT2 were captured, the last subdirectory would be \SLPT2). The job is spooled as a file, and then is loaded to an area in memory called the print buffer. From the print buffer, the print job is sent to the printer.
The print buffer speeds up the printing, because accessing memory is much faster than accessing a hard disk drive. The bigger the print buffer is, the fewer times the computer has to obtain information from the relatively slow hard drive, and the faster the printing is.
Print Buffer Configuration
Set the print buffer size to the maximum allowed value, unless limited memory is available.
Receive Buffers
Number of Receive Buffers
Each Netware Lite server has two types of buffers related to overall network communication, which can be configured by a supervisor. They are the receive and read buffers. Understanding receive and read buffers and how to configure them requires an understanding of some basic NetWare Lite network communication concepts.
When an application makes a request of DOS, such as reading data from a file or writing data to a file, DOS determines whether or not it can handle the request itself. If the requested operation involves a network resource, such as listing a network directory, DOS passes the request to the network, which fills the request and gives the response back to DOS, which in turn passes the response back to the application.
Each network request passes through four different stages before actually being sent out on the network cabling. The network provides information to DOS (e.g. which drives are actually network drives) so that DOS knows when to pass requests to the network, and when to return errors to the requesting application.
There are three programs which provide the interface to the network hardware. They are the Internetwork Packet Exchange Protocol (IPX) driver (IPXODI.COM), the Link Support Layer (LSL) driver (LSL.COM), and the Network Interface Card (NIC) driver (e.g. NE2000.COM). These three programs take requests from the network level and transforms them into packets which are then sent out on the cable.
When a packet is received at the server, SERVER.EXE is notified and the packet is placed in a free receive buffer. The server processes the request and then does one of two things: If the requested operation is a disk read, the server reads the requested amount of data and places the response in a free read buffer. If the request is for anything else, the server places the response back in the receive buffer where it got the request. The data is then transferred back across the network to the application that originally made the request.
Number of Receive Buffers Configuration Information
Set the number of receive buffers to three more than the number of clients that will be simultaneously accessing the server.
The extra receive buffers are important. The server may be servicing requests from every client on the network and still needs extra buffers to listen for additional incoming requests. Even though all client machines may have requests pending at the server, a client may re-send a request and the server needs extra buffers to handle any extra packets from the clients.
Receive Buffer Size Description and Configuration Information
The network is limited to the type of network hardware that is being used. A receive buffer cannot be set to anything larger than the packet size of a particular type of card. Typically ethernet is limited to a packet size of 1450 bytes and arcnet and token ring are capable of sending and receiving 4096 byte packets, the limit of NWLite.
DOS reads information best in 512 byte increments, so receive buffers should be set to a multiple of 512 bytes even if the packet size is larger than the 512 byte multiple. For example, when using ethernet cards, set the buffer size to 1024 bytes rather than the maximum allowed 1450 bytes. Because 1024 is an increment of 512, and the 1024 setting will be faster than 1450 bytes.
If you have a read buffer on one machine set to 512 bytes and the receive buffer on another machine set to 1024 bytes, the packets will be sent in 512 byte blocks rather than 1024 byte blocks. The receive buffers should be the same size as the read buffers on all machines in the network.
Read Buffers
Number of Read Buffers
Once information is read, it is placed in a read buffer and waits until the network is ready to send the information back to the requesting client. Each client machine can only reserve one read buffer on the server.
Number of Read Buffers Configuration Information.
Set the number of read buffers to the number of clients that will be simultaneously accessing the server. One read buffer per client. More than one per client will only waste memory since a client can use only one read buffer.
Read Buffer Size and Configuration Information
Read buffers are very similar to receive buffers. The purpose is slightly different as is explained above, but the guideline for setting the read buffer size is the same as the guideline for setting the receive buffer size. Set the read buffer size the same as the receive buffer size.
REMOTE MANAGEMENT
Allow Remote Management
If remote management is enabled, a network supervisor will be able to change a server's configuration settings from any machine on the network. If remote management is disabled, a server's configuration settings will only be able to be modified at the keyboard of the server itself.
Note: Remote Management does not refer to modem use.
Remote Management Configuration.
Enable or disable remote management depending upon the conditions in which the network is running. If security is a concern, remote management may need to be disabled.
FUTURE SERVER NAME
Future Server Name
The future server name is the name which the server will be called the next time the network is started.
SERVER STATUS SCREEN
Status Information for Server NWLite
Server up-time Days Hours Minutes Seconds
Server version CFG PEAK CURR
Server addres Connections
Network Auditing Client tasks
SHARE running Open files
Server memory size Num net directories
CUM Num net printers
Server-busy packets Print buffer size
Server cache hits Receive buffers
Packets Received Receive buffer size
Bad packets received Read buffers
Watchdog terminations Read buffer size
The Server status screen is a diagnostic tool that can be used to trouble-shoot problems within the network and to optimize the speed at which the network runs. All of the items listed on this screen are configured in other places; this screen only indicates what the current settings are.
The Server status screen has some distinguishing features. The right hand column contains the statistics set in the Server configuration menu. These statistics are listed in three columns. The CFG column shows how the items are currently configured, the PEAK column shows how close to the configured setting each item has gotten since the network was started, and the CURR setting shows the current status of each item. The PEAK and CURR numbers are dynamic, meaning any changes will immediately show on the screen. The left hand column contains information that is set when the machine is started and has cumulative information that keeps track of the total performance of the network since the network was started.
Server Up-time
This indicates how long the server has been running continuously since the network was loaded. Every time the network is restarted, the Server up-time figure is reset to zero.
Server Version
This displays the version of NetWare Lite that is currently running. The current version of NetWare Lite available is version 1.0.
Server Address
The server address is the node address of the network card that is installed in the server. The node address is a unique number assigned to the network card that distinguishes it from other cards on the network. This number may be set with software settings, switches on the card, or it may be built into the card.
Network Auditing
Network auditing has a "yes" or "no" indicator displaying whether or not the auditing feature has been enabled. The audit log lists such activities as logins, logouts, and backup of network management files. The date and username associated with each activity appear in the log. Network auditing can be turned on and off within the net utility in the Supervise the Network option.
SHARE Running
This screen let's you know whether or not SHARE.EXE has been loaded. SHARE is the DOS file used to control file locking and file sharing. SHARE is a necessary program to load when using a peer to peer network because it enables programs to be run concurrently and ensures proper file locking so two people do not access the same data file at the same time.
Server Memory Size
If this percentage is low, an increase of the number of read buffers may speed up your system.
Server-busy Packets
This statistic informs the user of the number of times that a client re-sends a request to a server when the server was too busy to handle the request. A large number of server-busy packets (more than 1%) usually indicates that the server is not fast enough to handle the volume of requests that are being made. A third-party disk cacheing program will improve the speed of the server and will reduce the number of server-busy packets.
Another event that will cause the server-busy packets to increase at an abnormal rate is when the server is formatting a floppy disk. DOS is not available during a disk format to service requests coming in from clients. As a result, many retries will be made from client machines causing the number of server-busy packets to increase.
Server Cache Hits
Percentage of requests serviced by the cache rather than accessing DOS. The cache will not be used for smaller files. If the server can service the incoming packet in one request, it will not use the cache. Usually files under 1024 bytes will not take advantage of the cache. The cache is directly related to the number and size of the read buffers. If the percentage is low, an increase of the number of read buffers may speed up the process.
Packets Received
The total number of packets received by the server.
Bad Packets Received
This number represents the number of times the server got a packet from the IPXODI that was damaged, possibly with a corrupt IPXODI header. Bad packets should rarely be received. If this number is non-zero, there could be a hardware problem--possibly the network card.
Watchdog Terminations
Netware Lite uses a process called the watchdog to verify whether or not a connection exists. In a server's connection table there is a timer associated with each connection. Whenever a packet is received from a client, the timer associated with that client is reset to zero. If no packets are received within five minutes, the server "calls" that computer by sending out a packet asking for a response. If the client computer responds, the server will reset the timer associated with that connection. If the computer does not answer within five minutes, the server will call again once a minute for ten more minutes. If no response is received from the "missing" computer, the server will remove the machine from the connection table and the client will have to re-establish a connection to access the server. The process of eliminating missing connections using watchdog terminations, is used to keep the connection table in each server as clean as possible.
Each client machine has a connection table where the computer keeps track of how many other machines it is connected to. Unlike the server, the client's connection table is not monitored by a watchdog and will not be disconnected if the connection is lost. When a connection is lost with a server, the client machine will return the message General failure reading device NWLite and will ask the user to abort, retry, or fail every time an operation that accesses the server is attempted while the server is down. When the connection is first re-established, the user will receive the same error, but pressing r for retry will re-establish the connection and carry out the requested operation.
Trouble shooting with the Server Status screen
The right hand columns of the Server status screen contains the current configuration, the peak level, and the current statistics of the items configured in the Server configuration menu with the exception of Open files. The CFG (configured) setting of Open files is the number of files that are defined in the config.sys file that DOS uses to configure the system when booting the computer. The rest of the items have been covered previously in this document.
A network administrator may use the three columns of information to fine tune his/her network. The items in the right hand column affect the size of the network in memory and the way the network operates. By monitoring the figures in the PEAK and CURR columns and comparing those with the number currently configured in the CFG column, a netowrk administrator may avoid wasting valuable memory and also verify that the network has plenty of room to operate.
If the highest recorded value for any of these attributes approaches 80 percent of the configured setting, a network administrator should consider increasing the configured setting. Three figures need to be regularly monitored. These three are the number of connections, client tasks and open files. As the highest values for these statistics approach or equal the corresponding configuration settings, unpredictable results can occur. These results can be anything from file locking problems, to data corruption, to the server crashing and locking the entire network.
By monitoring the statistics on the Server Status Screen, a network administrator can isolate problems before they become critical, avoid wasting valuable memory space that can be better used by other applications, and tune the network so that it will operate at the most optimal level.
