Description

The MFT_SAFE_MODE controls the behavior of manager fault tolerance (MFT) by specifying whether or not multiple hosts can be specified in the REMOTE_HOST option.

This MFT safe mode protects against problems that might arise when automated processing is used for manager fault tolerant UCMD Managers that specify multiple entries in a REMOTE_HOST list.

By default, MFT_SAFE_MODE is enabled, allowing only one host to be specified in REMOTE_HOST. If MFT_SAFE_MODE is disabled, multiple hosts can be specified.

For example, assume that a UCMD Manager, cancelled because of a failed network connection, was configured with the following:

REMOTE_HOST specifies multiple entries.
COMMAND_ID is static.
MANAGER_FAULT_TOLERANT = yes.
RESTART = no.

If the network connection is back up when the job is resubmitted, the Broker on the original host will only accept a restart request from the UCMD Manager. In this situation, the UCMD Manager would fail (as it should), and the operator would know to set the RESTART option to auto or yes, and to provide the original host for REMOTE_HOST.

However, if the network connection is still down when the job is resubmitted, or the UCMD Manager begins its connection attempts with a different host, a new UCMD Server instance — very likely duplicating work already performed by the original UCMD Server — will be started on a different system.

MFT_SAFE_MODE is ignored when the MANAGER_FAULT_TOLERANT option is set to no.

Valid MFT_SAFE_MODE values, and the MANAGER_FAULT_TOLERANT and REMOTE_HOST values that may be specified for each, are identified in the following #Values section.

Usage

Method	Syntax	IBM i	UNIX	Windows	z/OS
Command Line, Short Form	n/a
Command Line, Long Form	-mft_safe_mode option
Environment Variable	UCMDMFTSAFEMODE=option
Configuration File Keyword	mft_safe_mode option
STRUCM Parameter	MFTSAFMODE(*option)

Values

option is the specification for whether or not Manager Fault Tolerant (MFT) Safe Mode is enabled:

yes
MFT Safe Mode is enabled.
no
MFT Safe Mode is disabled.

Default is yes.

Combinations of MANAGER_FAULT_TOLERANT and MFT_SAFE_MODE settings, and how each affects what may be specified for REMOTE_HOST, are listed below.

MANAGER_FAULT_TOLERANT	RESTART	MFT_SAFE_MODE	REMOTE_HOST
No	n/a	Ignored	Multiple entries allowed.
Yes	No	Yes	Only 1 entry allowed. UCMD Manager will fail if multiple entries reside in the host list after entry is resolved, expanded, and scrubbed.
Yes	No	No	Multiple entries allowed. Use with caution; introduces duplicate processing risks described above.
Yes	Yes	n/a	Only 1 entry allowed (must match original remote system). UCMD Manager will fail if multiple entries specified, regardless of MFT_SAFE_MODE value.
Yes	Auto	n/a	Only 1 entry allowed. UCMD Manager will fail if multiple entries specified, regardless of MFT_SAFE_MODE value.

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