InfoScale™ 9.0 Storage and Availability Management for DB2 Databases - AIX, Linux
- Section I. Storage Foundation High Availability (SFHA) management solutions for DB2 databases
- Overview of Storage Foundation for Databases
- About Veritas File System
- Overview of Storage Foundation for Databases
- Section II. Deploying DB2 with InfoScale products
- Deployment options for DB2 in a Storage Foundation environment
- Deploying DB2 with Storage Foundation
- Deploying DB2 in an off-host configuration with Storage Foundation
- Deploying DB2 with High Availability
- Deployment options for DB2 in a Storage Foundation environment
- Section III. Configuring Storage Foundation for Database (SFDB) tools
- Configuring and managing the Storage Foundation for Databases repository database
- Configuring the Storage Foundation for Databases (SFDB) tools repository
- Configuring authentication for Storage Foundation for Databases (SFDB) tools
- Configuring and managing the Storage Foundation for Databases repository database
- Section IV. Improving DB2 database performance
- About database accelerators
- Improving database performance with Quick I/O
- About Quick I/O
- Improving DB2 database performance with Veritas Concurrent I/O
- Section V. Using point-in-time copies
- Understanding point-in-time copy methods
- Volume-level snapshots
- Storage Checkpoints
- Considerations for DB2 point-in-time copies
- Administering third-mirror break-off snapshots
- Administering Storage Checkpoints
- Database Storage Checkpoints for recovery
- Backing up and restoring with Netbackup in an SFHA environment
- Understanding point-in-time copy methods
- Section VI. Optimizing storage costs for DB2
- Section VII. Storage Foundation for Databases administrative reference
- Storage Foundation for Databases command reference
- Tuning for Storage Foundation for Databases
- Troubleshooting SFDB tools
Copy-on-write
In Figure: Updates to the primary fileset, the third data block in the primary fileset originally containing C is updated.
Before the data block is updated with new data, the original data is copied to the Storage Checkpoint. This is called the copy-on-write technique, which allows the Storage Checkpoint to preserve the image of the primary fileset when the Storage Checkpoint is taken.
Every update or write operation does not necessarily result in the process of copying data to the Storage Checkpoint because the old data needs to be saved only once. As blocks in the primary fileset continue to change, the Storage Checkpoint accumulates the original data blocks. In this example, subsequent updates to the third data block, now containing C', are not copied to the Storage Checkpoint because the original image of the block containing C is already saved.