HP StorageWorks XP Remote Web Console Software - Manual (Page 40)

2-18 Chapter 3 Preparing for Universal Replicator z/OS Operations
Hitachi Universal Replicator for IBM /OS User’s Guide
Error Reporting Communications (ERC)
Error reporting communications (ERC), which transfers information between
host processors at the primary and secondary sites, is a critical component of
any disaster recovery effort. You can configure ERC using channel-to-channel
communications, NetView technology, or other interconnect technologies,
depending on your installation requirements and standards. Neither URz nor
the URz remote console software provides ERC between the primary and
secondary sites.
When URz is used as a data migration tool, ERC is recommended but is not
required. When URz is used as a disaster recovery tool, ERC is required to
ensure effective disaster recovery operations. When a URz pair is suspended
due to an error condition, the primary storage system generates sense
information which results in an IEA491E system console message. This
information should be transferred to the primary site via the ERC for effective
disaster detection and recovery.
Remote Copy Operations
Figure 2-5 illustrates the two types of URz remote copy operations: initial copy
and update copy.
Primary host
Obtaining updated
journal data
Update copy
Write instruction
Secondary host
Initial copy
Obtaining base-journal
Primary storage system Secondary storage system
Restore
Secondary
data
volume
Restore
journal
volume
Primary
data
volume
Master
journal
volume
Figure 2-5 Remote copy operations
This section describes the following topics that are related to remote copy
operations with URz:
• Initial copy operation (see the next section)