Try to keep your groups to a manageable size; ideally, there should be
no more than about 100 resource definitions in a group. Allocate your resource
definitions between groups to obtain optimum performance, in both system and
administration terms. The following considerations may help:
- A large group can involve a lot of unnecessary processing time to install.
This is particularly true of those containing TERMINAL and SESSIONS definitions,
because they take a large amount of dynamic storage.
- A large number of very small groups can also use unnecessary processing
time, because of the extra I/O involved in reading many group names from the
CSD file. In theory, you could have one resource definition per group, but
this is not recommended; the processing of a large number of single-resource
groups can affect DASD space, initial or cold start performance, and the performance
of both CEDA and DFHCSDUP.
- Administration is easier if you have smaller groups. For example, the
DISPLAY GROUP ALL command involves a lot of scrolling if the resource definitions
in the group extend over many screens. You cannot see at a glance the contents
of a large group.
- You may find that you have storage problems when you EXPAND, COPY, or
INSTALL a large group. In particular, if a very large number of CSD file records
are defined in a region with a small dynamic storage area, issuing a CEDA
EXPAND GROUP(*) command can result in the system going short on storage (SOS).