RDF System Management Manual for H-Series RVUs (RDF 1.8)

Sizing the RDF configuration is a complex task that is best carried out by HP personnel. Those
personnel can assist you in configuring and sizing your RDF environment using tools and utilities
designed and developed as part of the RDF Professional Service.
Contact your service provider for further details.
Disk Volume Limit
The RDF/IMP, IMPX, and ZLT products can protect up to 255 physical or virtual volumes on
your primary system, and the updaters for these volumes replicate to either a single physical or
virtual disk on the backup system.
Volume-to-Volume Mapping
The recommended disk drive configuration for RDF products is a one-to-one mapping between
the primary volumes and their corresponding backup volumes, with mirrored disks on both
systems. This one-to-one mapping ensures that each partition of a partitioned file or table is
mapped appropriately to a backup volume.
Volume names on the backup system can differ from those on the primary system, but the use
of identical primary and backup volume names prevents naming conflicts after a takeover
operation. If the names of the backup volumes are different than those of the corresponding
primary volumes, you will need to change all volume references before the primary system’s
applications can start on the backup system.
Subvolume-to-Subvolume Name Mapping
RDF can replicate data from subvolumes on the primary system to same or differently named
subvolumes on the backup system. For more information, see Chapter 12 (page 265).
Data Communication (Expand) Resources
RDF sends filtered audit data from the primary system over the network to the backup system.
A communications path between the systems can be any form of Expand linkage. Plan to configure
sufficient communications resources between the primary and backup systems so that RDF can
do the following:
• Handle the peak rate of audit data
• Catch up processing in any audit trail if the communications paths go down and are restored
(without RDF reinitialization)
If you are using a dedicated Expand path with high throughput, you should set
PATHPACKETBYTES to 8192. If you are not using a dedicated Expand path, you should use
Multipacket frames with PATHBLOCKBYTES set to 8192. See also “Specifying System Generation
Parameters for an RDF Environment” (page 69).
RDF is designed to extract audit information from the primary system and transmit it to the
backup system as quickly as possible. If you are not using the ZLT capability, this limits the
number of transactions that could be lost if a disaster should occur at the primary system. See
Unplanned Outages Without ZLT in Chapter 1 (page 35).
To estimate the data communications resources needed for RDF, calculate the amount of audit-trail
data generated per second during peak loads. If your business has seasonal peaks, such as
holidays or the ends of calendar quarters, consider the peak rate at those times.
The discussion that follows pertains to the Master Audit Trail (MAT). If you are replicating
auxiliary audit trails, you should use the same algorithm for each auxiliary audit trail.
Use the following sampling process once an hour for two weeks to establish your needs:
64 Preparing the RDF Environment