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
DB2_PARALLEL_IO
This setting is used to force parallel I/O to occur on tablespaces. This is important in combination with the DB2_STRIPED_CONTAINERS setting, as RAID devices have more than one physical disk and therefore can sustain a greater I/O load than non-RAID devices. DB2 achieves this parallelism by enabling multiple prefetch threads on enabled tablespaces.
The DB2_PARALLEL_IO variable is set using the db2set command. To enable parallel I/O on all tablespaces, you would run the commands:
$ db2set DB2_PARALLEL_IO=* $ db2stop ; db2start
To enable parallel I/O on a subset of all tablespaces, you need to know the tablespace identifying number and supply a list of tablespace ids, comma separated, to the db2set command:
$ db2 connect to PROD $ db2 list tablespaces $ db2 terminate $ db2set DB2_PARALLEL_IO=3,4,8,9 $ db2stop ; db2start
As per the examples, you must stop and restart your instance after modifying the DB2_PARALLEL_IO setting. It is also recommended that DB2_PARALLEL_IO be enabled for tablespaces residing on RAID devices when PREFETCHSIZE > EXTENTSIZE.