2. USAGE GUIDELINES › 2.2 Product Usage Considerations
2.2 Product Usage Considerations
This section identifies some of the factors you should
consider when setting VM Data Transfer Program parameters:
o Frequency of data transfer
If you are sending data from VM to MVS by tape, the
frequency of transfer can be as low as once a day,
provided you have enough VM spool space or disk space
to hold the original data. Your Systems Programmer
can assist you in evaluating the frequency of data
transfer for your system.
However, if you are sending data by NJE (that is,
SPOOL), you should consider sending the data more
frequently, especially if your installation has large
VM systems.
In determining the frequency of transmission, consider
the following:
- Large amounts of VM Monitor data take up
considerable spool space. VM Monitor files tend to
be voluminous. Your VM System Administrator can
assist you in determining the appropriate setup for
your installation.
- NJE network throughput is installation-dependent.
This is especially true if you are not using a
channel-to-channel adaptor to pass files between
RSCS and JES. RSCS V2 or above can use more than
one job transmitter. Review your NJE setup to help
you determine the optimal volume of data to be
transferred through the network at one time.
- Spool-network architecture does not permit
transmission of VM Monitor data in its original
form. The VM Data Transfer Program utilizes
internal interfaces to bypass this problem.
During a transfer, VM data is read from the VM
spool and written back into the VM spool in 80-byte
card images without intermediate disk storage. The
amount of data for the file being read is doubled
because the input file is not purged until it is
completely read.
While the input file exists in its entirety, the
output file is expanded until all data from the
input file is read. (If record selection is being
used, the volume of output data can be
significantly less than the input data.)
o Retaining spool files
Input Account or VM Monitor files can be held in the
spool after processing, to be passed to another
application or archived. Note: The considerations
for spool occupancy, discussed above, also apply here.
o Record selection
The VM Data Transfer Program allows selective transfer
of data, reducing NJE network load and the amount of
data that is sent to the MVS system. Selective
transfer can also reduce the time required to run the
CA MICS VM and CMS Analyzer Daily update.
We recommend the following selections.
- domains 0, 1, 4, 5, and 6 of VM Monitor
records; only select domain 4, record types 8, 9,
and 10, if user-level transaction analysis is
required
- types 1 (Resource), 2 (Dedicated Device), and 3
(T-Disk) of VM Account records
o Data compression
A data compression technique is provided as a means of
further reducing the volume of data to be passed
through your NJE network. The amount of data
compression is installation-dependent, based on your
data mix, VM system configuration, and the VM system
activity when the data was produced.
o Input data archive
The VM Data Transfer Program provides an archive
function for saving input data. If you use this
function, a copy of the original input data is saved
on disk or tape before record selection is performed.
Should the need arise, the original data can be
restored and re-transmitted.
o Output data duplex
The VM Data Transfer Program provides a duplex
function that prevents data loss due to network
outages and similar abnormal conditions. If you use
this function, a copy of the output data produced by
the VM Data Transfer Program is saved on disk or tape
after the record selection process but before data
compression.
