TMF Reference Manual (G06.26+)

TMFCOM Commands
HP NonStop TMF Reference Manual—522418-003
3-70
ALTER AUDITTRAIL
The relationship between COMMITHOLDMODE and COMMITHOLD is as follows:
An ALTER AUDITTRAIL command that specifies the COMMITHOLDMODE or
COMMITHOLDTIMER option (or both of these options) cannot specify any other
options available with this command. Although you specify the COMMITHOLDTIMER
option for the master audit trail, this option really applies across the TMF system: the
commit-hold timer is started by the first audit trail to activate the commit-hold condition,
and continues to run as long as any audit trail has the commit-hold condition activated.
When you turn COMMITHOLDMODE to OFF, TMF retains all related settings
(including the COMMITHOLDTIMER timer and timeout options, discussed below) at
their present values.
As a general guideline, you might want to defer transaction processing (allow commit-
hold) in either of these two cases:
•
During a brief rolling outage, when you know the primary system is going to fail
anyway. Such an outage might result from a failed processor that will take down
the system in just a few seconds or a transient power failure that will interrupt
transactions in mid-process.
•
When the backup system becomes inaccessible for any reason, including a system
crash or a fire in the computer room that burns through the communication line and
ultimately destroys the system.
In most cases, your goal is to maximize transaction-backup protection on the backup
system while minimizing impact on transaction processing on the primary system.
Therefore, to guard against a rolling outage, you might set COMMITHOLDTIMER to a
value between 10 to 30 seconds. At the end of that period, if the primary system again
becomes available, transaction completion (commit or abort) resumes even if the
backup system is unavailable.
COMMITHOLDMODE
Setting
COMMITHOLD
Status and Meaning
OFF OFF: COMMITHOLDMODE is set OFF; the commit-hold
condition cannot be enabled, activated, or suspended.
ON ENABLED: COMMITHOLDMODE has been set ON, and
transaction completion can take place normally. This status is the
normal COMMITHOLD status. However, the commit-hold
condition can now be activated if conditions on the backup
system require the commit-hold condition.
ON ACTIVATED: The commit-hold condition is activated, and
transaction commits and aborts are currently on hold. The
timeout duration, if specified, is now in effect and the duration
timer is counting down.
ON REVIVING: Although commit-hold could not be guaranteed and
the audit trail entered the ACTIVATED state, the disk process can
now access the remote mirror successfully and is synchronizing
the remote mirror with the primary mirror. Once this
synchronization is complete, ZLT can be guaranteed once more.