RDF System Management Manual
Table Of Contents
- RDF System Management Manual
- What’s New in This Manual
- About This Manual
- 1 Introducing RDF
- RDF Subsystem Overview
- RDF Processes
- RDF Operations
- Reciprocal and Chain Replication
- Available Types of Replication to Multiple Backup Systems
- Triple Contingency
- Loopback Configuration (Single System)
- Online Product Initialization
- Online Database Synchronization
- Online Dumps
- Subvolume- and File-Level Replication
- Shared Access DDL Operations
- EMS Support
- SMF Support
- RTD Warning Thresholds
- Process-Lockstep Operation
- Support for Network Transactions
- RDF and NonStop SQL/MX
- Zero Lost Transactions (ZLT)
- Monitoring RDF Entities With ASAP
- 2 Preparing the RDF Environment
- 3 Installing and Configuring RDF
- 4 Operating and Monitoring RDF
- 5 Managing RDF
- Recovering From File System Errors
- Handling Disk Space Problems
- Responding to Operational Failures
- Stopping RDF
- Restarting RDF
- Carrying Out a Planned Switchover
- Takeover Operations
- Reading the Backup Database
- Access to Backup Databases in a Consistent State
- RDF and NonStop SQL/MP DDL Operations
- RDF and NonStop SQL/MX Operations
- Backing Up Image Trail Files
- Making Online Dumps With Updaters Running
- Doing FUP RELOAD Operations With Updaters Running
- Exception File Optimization
- Switching Disks on Updater UPDATEVOLUMES
- 6 Maintaining the Databases
- 7 Online Database Synchronization
- 8 Entering RDFCOM Commands
- 9 Entering RDFSCAN Commands
- 10 Triple Contingency
- 11 Subvolume- and File-Level Replication
- 12 Auxiliary Audit Trails
- 13 Network Transactions
- Configuration Changes
- RDF Network Control Files
- Normal RDF Processing Within a Network Environment
- RDF Takeovers Within a Network Environment
- Takeover Phase 1 – Local Undo
- Takeover Phase 2 – File Undo
- Takeover Phase 3 – Network Undo
- Takeover Phase 3 Performance
- Communication Failures During Phase 3 Takeover Processing
- Takeover Delays and Purger Restarts
- Takeover Restartability
- Takeover and File Recovery
- The Effects of Undoing Network Transactions
- Takeover and the RETAINCOUNT Value
- Network Configurations and Shared Access NonStop SQL/MP DDL Operations
- Network Validation and Considerations
- RDF Re-Initialization in a Network Environment
- RDF Networks and ABORT or STOP RDF Operations
- RDF Networks and Stop-Update-to-Time Operations
- Sample Configurations
- RDFCOM STATUS Display
- 14 Process-Lockstep Operation
- Starting a Lockstep Operation
- The DoLockstep Procedure
- The Lockstep Transaction
- RDF Lockstep File
- Multiple Concurrent Lockstep Operations
- The Lockstep Gateway Process
- Disabling Lockstep
- Reenabling Lockstep
- Lockstep Performance Ramifications
- Lockstep and Auxiliary Audit Trails
- Lockstep and Network Transactions
- Lockstep Operation Event Messages
- 15 NonStop SQL/MX and RDF
- Including and Excluding SQL/MX Objects
- Obtaining ANSI Object Names From Updater Event Messages
- Creating NonStop SQL/MX Primary and Backup Databases from Scratch
- Creating a NonStop SQL/MX Backup Database From an Existing Primary Database
- Online Database Synchronization With NonStop SQL/MX Objects
- Offline Synchronization for a Single Partition
- Online Synchronization for a Single Partition
- Correcting Incorrect NonStop SQL/MX Name Mapping
- Consideration for Creating Backup Tables
- Restoring to a Specific Location
- Comparing NonStop SQL/MX Tables
- 16 Zero Lost Transactions (ZLT)
- A RDF Command Summary
- B Additional Reference Information
- C Messages
- D Operational Limits
- E Using ASAP
- Index
HP NonStop RDF System Management Manual—524388-003
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7
Online Database Synchronization
With RDF/IMP, IMPX, or ZLT you can synchronize entire databases or selected
volumes, files, tables or even partitions while your applications continue to run.
For NonStop SQL/MX databases, see Section 15, NonStop SQL/MX and RDF.
Overview
The RDF online database synchronization protocol consists of the following general
steps (the details of which are discussed later in this section):
•
initialize the RDF configuration with the SYNCHDBTIME option.
•
issue a START RDF, UPDATE OFF command.
•
create an empty copy of the database
•
load the data from the actual database into the copy with shared access. Because
the load operation with shared access reads through transaction locks held by
applications, the resulting file is inconsistent with respect to transactions, but it is
consistent with respect to its physical state.
•
When the loads have completed and the copy of the database is on the backup
system, issue a START UPDATE command. As the updaters start applying audit,
they put the backup database to a consistent state with regard to transactions.
The RDF online database synchronization protocol can be used to synchronize entire
databases or selected parts of databases. The operations can be complex, depending
upon the database system being used (NonStop SQL/MP, NonStop SQL/MX, or
Enscribe), the file types being used (key-sequenced and relative), and whether you
need to synchronize an entire database or just selected portions. If you need to
synchronize entire databases, you should carefully read the sections “Synchronizing
Entire Databases Online” and “Considerations When Synchronizing Entire Databases”
first.
Because you must run RDF with UPDATE OFF while you load the empty copy of the
database, audit data will collect in the RDF image trails before you can eventually start
the updaters. Therefore, if your database is very large, you might want to consider
synchronizing several volumes at a time (synchronize a subset of volumes and then
Note. Entry-sequenced files and tables, unstructured files, and NonStop SQL/MP
tables that have SYSKEYs or clustering keys cannot be synchronized with the
methods described below. For those types of files, you must synchronize them offline.