At least one of the following optional keywords must be specified
with the function PTPMC:
- ACCESS
- COPYMODE
- COPYOPER
- IOLIB
If an optional keyword is not specified, the current setting
for that option is retained. The operational modes specified are applied
to all IBM® TotalStorage Virtual
Tape Controllers (AX0).
- IOLIB=PRIMARY
- Specifies a request to set the distributed library that is to
be selected for all host I/O operations; this makes the selected library
the master library. During mount processing, if the primary VTS is
not available, the mount request is failed. If the VTS does not have
a valid version of the volume, and a valid version is available on
another VTS, a copy operation is performed as part of the mount process.
If a valid version cannot be copied, the mount is failed. If the specified
VTS does not have the needed volume in cache, and it is in cache in
another VTS, a copy operation is also performed. If the needed volume
is not in cache in any available VTS, a recall is performed on the
specified VTS. The library specified for LIBNAME must be
a distributed library.
Note: If you are setting IOLIB=PRIMARY and the specified distributed library is not currently the master
library, the completion of this request can take up to 20 minutes.
- IOLIB=PREFERRED
- Specifies a request to set the preferred distributed library
for host I/O operations. The preferencing is honored as long as the
VTS library specified is available and has a valid version of the
volume in its cache, and as long as another available VTS does not
have the volume in its cache. The library specified for LIBNAME must
be a distributed library.
- IOLIB=BALANCED
- Specifies a request to let the library balance the workload
across all the VTS libraries in the Peer-to-Peer VTS configuration.
The balance of the workload is the primary criterion for selection
of the VTS to perform host I/O operations.
- IOLIB=DEFAULT
- Specifies a request to use the customer engineer's default
I/O selection setting on the AX0s for host I/O operations.
- COPYMODE=IMMEDIATE
- Specifies a request to set the copy mode to IMMEDIATE.
With this setting, a copy of the data is made upon receiving the host
rewind/unload (RUN) command. The completion of the rewind/unload (RUN)
command is held until the copy has been made.
- COPYMODE=DEFERRED
- Specifies a request to set the copy mode to DEFERRED.
With this setting, upon receiving the host rewind/unload (RUN) command,
the copying of the data is queued.
- COPYMODE=DEFAULT
- Specifies a request to use the customer engineer's copy
mode setting and the customer engineer's deferred mode priority
threshold value on the AX0s.
- DEFVALUE=deferred-priority-threshold
- Specifies the name of a bit variable (1-byte length) that contains
the number of hours between 0 and 255 for the deferred copy mode priority
threshold value. If a copy operation has been queued longer than the
number of hours specified by the deferred copy mode priority threshold
value, when it is selected for processing, it is given a higher I/O
priority than host I/O operations. This specified parameter value
affects copy operations that are initiated after the successful completion
of this command.
This parameter is only applicable with the COPYMODE=DEFERRED specification and is ignored with any other FUNC=PTPMC specification.
If COPYMODE=DEFERRED is specified without this parameter,
the current deferred mode priority threshold value is retained.
- COPYOPER=ENABLE
- Specifies a request to enable copy operations that have been
previously disabled.
- COPYOPER=DISABLE
- Specifies a request to disable copy operations. Copies currently
in progress are completed. Subsequent copies are queued to be performed
later when copy operations are enabled again.
- ACCESS=RWDISCON
- Specifies a request to enable the access mode of Read/Write
Disconnected, a special mode that allows controlled access to data
when one or more elements of a PTP VTS become unavailable and prevent
normal operations. The Read/Write Disconnected mode allows logical
volumes to be read, modified, or rewritten, unless the volumes are
known to be invalid. This mode forces the available VTS to become
the master; it should only be set for one VTS. This mode is no longer
in effect when communication with both VTSs has been established and
token updates have been completed.
The library specified for LIBNAME must be a distributed library. IOLIB, COPYMODE,
and COPYOPER specifications are ignored at the library when
the ACCESS keyword is specified.
Note: Check
with your hardware support center for the availability of the Read/Write
Disconnected option through this interface. If the installed microcode
does not support this option, it will be ignored.