RDF/IMP and IMPX System Management Manual (RDF 1.4+)

Preparing the RDF Environment
HP NonStop RDF/IMP and IMPX System Management Manual—524388-001
2-8
Specifying System Generation Parameters for an
RDF Environment
Specifying System Generation Parameters for an RDF
Environment
When performing system generation, you should do as follows:
•
Use the PATHPACKETBYTES modifier to enable the Expand Variable Packetsize
feature so that Expand will send large packets.
•
Use the CONGCTRL modifier to enable Expand congestion control.
•
Use the AUDITTRAILBUFFER parameter to improve RDF extractor performance
(set to the highest value).
You might also want to enable the multipacket frame feature, depending upon the type
of traffic that will be passed over the Expand path.
For best results, consider using the RDF Professional Service to assist you in defining
the Expand requirements for your RDF environment. Contact your service provider for
further details.
Designing Transactions for RDF Protection
When designing applications containing transactions that update databases protected
by RDF, you must consider the following restrictions that apply to the subsystem:
•
The effects of network (distributed) transactions after an RDF takeover operation
•
Database operations not replicated by RDF
The subsections that follow explain these restrictions.
Replicating Database Operations
Database administrators preparing to work with RDF should be aware of
considerations concerning:
•
NonStop SQL Data Definition Language (DDL) operations
•
Enscribe file-label modifications
•
Purge operations
•
Partitioned files
•
Temporary disk files
NonStop SQL DDL Operations
Although RDF replicates NonStop SQL Data Manipulation Language (DML)
operations, it does not replicate NonStop SQL Data Definition Language (DDL)
operations except for PURGEDATA. Excluding PURGEDATA, the database
administrator needs to perform all other DDL operations manually on the backup