RDF/IMP, IMPX, and ZLT System Management Manual

Zero Lost Transactions (ZLT)
HP NonStop RDF/IMP, IMPX, and ZLT System Management Manual—524388-002
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Recovering the Primary System After an RDF ZLT
Ta ke ove r
Recovering the Primary System After an RDF
ZLT Takeover
When the primary system is once again available for use, perform the following steps
to recover it after having performed an RDF ZLT takeover:
1. Disconnect all local audit-trail mirrors from the primary system, and then connect
all remote audit-trail mirrors to the primary system.
2. Start the primary system.
3. Start TMF on the primary system. During startup, volume recovery uses the remote
mirrors, thereby processing the same data that RDF did during ZLT processing.
When volume recovery is finished, the primary database is in the same state as
the backup database was after the ZLT takeover operation completed.
4. Reconnect the local audit-trail mirrors to the primary system, and then refresh the
local mirrors from the remote mirrors.
STOP TMF Operations
Within an RDF environment that is configured for ZLT processing, STOP TMF
operations are handled as follows.
During Normal Operations
If updating is off, the shutdown audit-record is not stored in image trails, and the
monitor, extractor(s), receiver(s), and purger RDF processes stop.
If updating is on, the shutdown audit-record is stored in image trails, and all RDF
processes stop.
During ZLT Takeover Processing
The shutdown audit-record is not stored in image trails, and all RDF processes
continue running.
The goal of ZLT processing is to catch up data as quickly as possible. Thus, there is no
point in stopping RDF processes if a STOP TMF record is found in the master audit-
trail (MAT).