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
Introducing RDF
HP NonStop RDF System Management Manual—524388-003
1-7
Planned Outages
When the program detects a successful RDF Takeover, it can then route requestor
work to the servers on the backup system, and those servers are then ready to resume
business on the backup system.
An alternative, and preferred, approach is to configure a takeover trigger to send a
message to the requester routing program.
Of course, what makes this method work is ensuring that no work is ever routed to the
backup system until the takeover has completed.
Planned Outages
RDF can be very useful when a planned shutdown of the primary system is necessary.
For example, you might need to bring the system down to install new hardware or to
perform a system software upgrade. In such a situation, you might determine it is
unacceptable to stop your business applications for the time required.
With RDF, you need only stop the applications momentarily, do a switchover from the
primary system to the backup system, and then restart the applications on the backup
system. When the primary system is ready for use again, you can use RDF to bring the
primary database up-to-date with changes made to the backup database while the
primary system was shut down. After the primary database is consistent with the
backup database, you can perform another switchover, this time from the backup
system to the primary system, and then restart the applications on the primary system.
For instructions on how to perform a switchover, see Carrying Out a Planned
Switchover.
Features
In providing backup protection for online databases, RDF offers many advantages:
•
Continuous Availability
RDF maintains an online copy of your production database on
one or more backup systems. If the primary system should go down, the backup
database(s) will be consistent and you can resume your business processing on a
backup system with minimal interruption and data loss.
•
Fault tolerance
You can restart RDF after a system crash. Single processor failures do not bring
the subsystem down. If a double processor failure occurs, RDF goes down, but it is
restartable with no loss of data (issue a START RDF command after the
processors have been restored).
•
High performance
RDF can typically replicate data from the primary RDF node as fast as the
customer application is capable of generating it.