NS3000/iX Operations and Maintenance Reference Manual (36922-90039)

154 Chapter7
Commands
NSCONTROL SERVER
the Network Services. If there are more concurrent users than the
minimum number of servers specified, new users can use the Network
Services, but there is a delay while the additional servers are created.
There is no simple formula for determining how many precreated
servers to specify. Since each precreated server consumes one set of
process resources, including process related system table entries and
virtual memory for stack space, the number chosen must be a tradeoff
between using system resources and allowing fast service response. The
node manager needs to estimate, on the average, the number of
concurrent users of each type of server. This number is used for the
minimum number of servers of each type. Since the DSSERVER process
is used by several services, and some of these services are active for a
long time, it makes sense to allocate a larger number of DSSERVER
servers than NFT, VTSERVER, LOOPBACK or NSSTATUS servers.
An alternative to allocating a greater number of DSSERVER servers is to
allocate the program files NFT.NET.SYS, VTSERVER.NET.SYS,
DSSERVER.NET.SYS, LOOPBACK.NET.SYS, and NSSTATUS.NET.SYS.
This alternative is most advantageous for DSSERVER, where the
allocation of the program file is a significant portion of the set up time.
The NFT server must read keywords and messages from the NFTCAT2
catalog as well as allocate the program file when the server is created,
so the performance gain is not as great as for DSSERVER.
Creating reserved servers or using the allocation alternative means
that the program file is in use, just as when a program is run. Since the
program file is in use, it cannot be purged, replaced, or backed up.
Before any software installation, when the program files are replaced or
backed up, check that the program files are not allocated and that there
are no reserved servers.
Example
The following command sets the minimum number of DSSERVER
processes to five and the maximum to 10. Five reserved DSSERVER
processes are created immediately and are available for future service
requests. The minimum number of servers, which includes both
reserved and active servers, is restricted to five. When an active server
is returned to the reserved pool, if there are already five reserved
servers, the extra server is terminated. The maximum limit means that
if there are 10 DSSERVER processes active, any new service requests
will be rejected.
:NSCONTROL SERVER=DSSERVER,5,10