4. FILES › 5.2 VTS Component Files › 5.2.2 VTS Component IVT Information Area Files › 5.2.2.1 VTS Distributed Library Activity File (IVTVDL) › 5.2.2.1.3 IVTVDL Usage Considerations

5.2.2.1.3 IVTVDL Usage Considerations

This section identifies any special considerations or
techniques related to using the IVTVDL file.

For reporting purposes, it is important to examine data
element VTS Type (IVTTYPE).  IVTTYPE can take on up to three
values in the IVTVDL file; 'STANDALONE', 'UI', and
'SECONDARY'.

For IVTVDL observations where the IVTTYPE='STANDALONE', the
VTS is an autonomous virtual tape server.

For IVTVDL observations where the IVTTYPE='UI' or
'SECONDARY', however, the VTS is a participant in a
peer-to-peer configuration.  All peer-to-peer VTS
configurations have two IVTVDL observations and one VTS
Composite Library Activity (IVTVCL) file observation for each
hour in the DETAIL and DAYS timespans.

Data element Composite Library Association (IVTCMPID)
contains the same value for all three observations and is
used to identify all participating VTSs in a peer-to-peer
configuration.

In general, the two hourly IVTVDL observations ('UI' and
'SECONDARY') for a peer-to-peer configuration, contain the
statistics related to the virtual volume, DASD cache, and
physical cartridge activity related to their half of the
configuration.

The hourly IVTVCL observation contains the composite, or
logical view of the peer-to-peer VTS and provides overall
z/OS throughput and virtual volume activity statistics.