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
About extents
An extent is a contiguous area of storage in a computer file system, reserved for a file. When starting to write to a file, a whole extent is allocated. When writing to the file again, the data continues where the previous write left off. This reduces or eliminates file fragmentation. An extent is presented as an address-length pair, which identifies the starting block address and the length of the extent (in file system or logical blocks). Since File System (VxFS) is an extent-based file system, addressing is done through extents (which can consist of multiple blocks) rather than in single-block segments. Extents can therefore enhance file system throughput.
Extents allow disk I/O to take place in units of multiple blocks if storage is allocated in contiguous blocks. For sequential I/O, multiple block operations are considerably faster than block-at-a-time operations; almost all disk drives accept I/O operations on multiple blocks.
Extent allocation only slightly alters the interpretation of addressed blocks from the inode structure compared to block-based inodes. A VxFS inode references 10 direct extents, each of which are pairs of starting block addresses and lengths in blocks.
Disk space is allocated in 512-byte sectors to form logical blocks. VxFS supports logical block sizes of 1024, 2048, 4096, and 8192 bytes. The default block size is 1 KB for file system sizes of up to 2 TB, and 8 KB for file system sizes 2 TB or larger.