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
- Introducing Storage Foundation High Availability (SFHA) Solutions for DB2
- About the File System component
- About the Volume Manager component
- About Dynamic Multi-Pathing (DMP)
- About Cluster Server
- About Cluster Server agents
- About InfoScale Operations Manager
- Feature support for DB2 across InfoScale products
- Use cases for InfoScale products
- Overview of Storage Foundation for Databases
- Section II. Deploying DB2 with InfoScale products
- Deployment options for DB2 in a Storage Foundation environment
- DB2 deployment options in an InfoScale environment
- DB2 on a single system with Storage Foundation
- DB2 on a single system with off-host in a Storage Foundation environment
- DB2 in a highly available cluster with Storage Foundation High Availability
- DB2 in a parallel cluster with SF Cluster File System HA
- Deploying DB2 and Storage Foundation in a virtualization environment
- Deploying DB2 with Storage Foundation SmartMove and Thin Provisioning
- 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
- About the Storage Foundation for Databases (SFDB) repository
- Requirements for Storage Foundation for Databases (SFDB) tools
- Storage Foundation for Databases (SFDB) tools availability
- Configuring the Storage Foundation for Databases (SFDB) tools repository
- Updating the Storage Foundation for Databases (SFDB) repository after adding a node
- Updating the Storage Foundation for Databases (SFDB) repository after removing a node
- Removing the Storage Foundation for Databases (SFDB) 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
- How Quick I/O improves database performance
- Tasks for setting up Quick I/O in a database environment
- Preallocating space for Quick I/O files using the setext command
- Accessing regular VxFS files as Quick I/O files
- Converting DB2 containers to Quick I/O files
- About sparse files
- Displaying Quick I/O status and file attributes
- Extending a Quick I/O file
- Monitoring tablespace free space with DB2 and extending tablespace containers
- Recreating Quick I/O files after restoring a database
- Disabling Quick I/O
- Improving DB2 database performance with VxFS Concurrent I/O
- Section V. Using point-in-time copies
- Understanding point-in-time copy methods
- About point-in-time copies
- When to use point-in-time copies
- About Storage Foundation point-in-time copy technologies
- Point-in-time copy solutions supported by SFDB tools
- About snapshot modes supported by Storage Foundation for Databases (SFDB) tools
- Volume-level snapshots
- Storage Checkpoints
- Considerations for DB2 point-in-time copies
- Administering third-mirror break-off snapshots
- Administering Storage Checkpoints
- About Storage Checkpoints
- Database Storage Checkpoints for recovery
- Creating a Database Storage Checkpoint
- Deleting a Database Storage Checkpoint
- Mounting a Database Storage Checkpoint
- Unmounting a Database Storage Checkpoint
- Creating a database clone using a Database Storage Checkpoint
- Restoring database from a Database Storage Checkpoint
- Gathering data for offline-mode Database Storage Checkpoints
- 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
How Quick I/O improves database performance
The benefits of using Quick I/O are:
Improved performance and processing throughput by having Quick I/O files act as raw devices.
Ability to manage Quick I/O files as regular files, which simplifies administrative tasks such as allocating, moving, copying, resizing, and backing up DB2 containers.
Note:
Quick I/O is not supported on Linux.
Quick I/O's ability to access regular files as raw devices improves database performance by:
Table:
Quick I/O feature | Advantage |
|---|---|
Supporting direct I/O | I/O on files using read() and write() system calls typically results in data being copied twice: once between user and kernel space, and later between kernel space and disk. In contrast, I/O on raw devices is direct. That is, data is copied directly between user space and disk, saving one level of copying. As with I/O on raw devices, Quick I/O avoids extra copying. |
Avoiding kernel write locks on database files | When database I/O is performed using the write() system call, each system call acquires and releases a write lock inside the kernel. This lock prevents multiple simultaneous write operations on the same file. Because database systems usually implement their own locking to manage concurrent access to files, per file writer locks unnecessarily serialize I/O operations. Quick I/O bypasses file system per file locking and lets the database server control data access. |
Avoiding double buffering | Most database servers maintain their own buffer cache and do not need the file system buffer cache. Database data cached in the file system buffer is therefore redundant and results in wasted memory and extra system CPU utilization to manage the buffer. By supporting direct I/O, Quick I/O eliminates double buffering. Data is copied directly between the relational database management system (RDBMS) cache and disk, which lowers CPU utilization and frees up memory that can then be used by the database server buffer cache to further improve transaction processing throughput. |
For AIX: Supporting AIX Fastpath asynchronous I/O | AIX Fastpath asynchronous I/O is a form of I/O that performs non-blocking system level reads and writes, allowing the system to handle multiple I/O requests simultaneously. Operating systems such as AIX provide support for asynchronous I/O on raw devices, but not on regular files. As a result, even if the database server is capable of using asynchronous I/O, it cannot issue asynchronous I/O requests when the database runs on file systems. Lack of asynchronous I/O significantly degrades performance. Quick I/O lets the database server take advantage of kernel-supported asynchronous I/O on file system files accessed using the Quick I/O interface. |