Chapter 3. Operating NetView FTP V2.2.1 MVS - IBM

The Compression Method Used
Server Classes
AVLRRH Number of remote file transfers
For an OSI server this parameter must be set to zero because an
OSI server is only used for locally initiated file transfers.
When selecting values for the preceding parameters, the system administrator
must consider the following factors:
– The total of the amount of automatic and dynamic storage per server that
must be allocated, as follows:
- Automatic space for each possible concurrent file transfer; determined
by the MAXSESS values for the server.
- Dynamic space for each active file transfer.
– The probability of queuing bottlenecks, due to the server or servers for a
particular request class not having enough sessions available to process
the requests in that class.
The originator of a file-transfer request can specify any of the following types of
compression:
NONE No compression is used
ADAPT Adaptive compression is used
SNA SNA-type compression is used.
The type of data to be transferred determines which of these methods is the most
effective (see the NetView FTP Parameter Reference for more information about
compression methods). The system administrator must take the following into consideration
when determining which type of compression should be used on the
system:
� No compression uses the least CPU time, but usually involves the transfer of
the greatest amount of data.
� Adaptive compression uses the most CPU time, but usually involves the
transfer of the least amount of data. This is the most effective method for most
types of data.
� SNA compression involves less CPU time than adaptive compression, but
usually involves the transfer of more data.
The system administrator can then advise the users on the type of compression
they should use.
When setting up the classes of request that the servers on a system can process,
the system administrator must take the following into consideration:
� The general requirements of the installation.
� The speed with which requests of a particular class are processed depends on
the total number of local request handlers that are available to process
requests of that class. This is determined by the sum of the AVLLRH server
initialization parameter values of all started servers that can process requests
of that class.
Appendix E. Factors That Affect the Performance of NetView FTP V2.2.1 MVS 211