Veritas™ File System Programmer's Reference Guide - Solaris
- Veritas File System software developer's kit
- File Change Log
- About the File Change Log file
- Record types
- File Change Log tunables
- Application programming interface for File Change Log
- API functions
- File Change Log record
- Copying File Change Log records
- Veritas File System and File Change Log upgrade and downgrade
- Reverse path name lookup
- Multi-volume support
- Named data streams
- Veritas File System I/O
- Caching advisories
- Extents
- Thin Reclamation
Veritas File System and File Change Log upgrade and downgrade
VxFS 4.1 supported only FCL Version 3. VxFS 5.0 and later releases support both FCL Version 3 and 4, with Version 4 as the default. When a system is upgraded from VxFS 4.1 to VxFS 5.0 or a later release, and the file system has FCL switched on, the existing Version 3 FCL files remains as is. VxFS 5.0 and later releases continue tracking file system changes in the Version 3 FCL exactly as it was done by VxFS 4.1.
A VxFS 4.1 application that directly accesses the FCL file using the read(2) system call can still continue to work in VxFS 5.0 and later releases, provided that the FCL file is Version 3. However, you must develop any new applications using the API. The API has support for both FCL Versions 3 and 4.
If a new application uses the record types that were added in the VxFS 5.0 release, such as file opens or access information, the FCL needs to be at Version 4.
If you are running applications that still read FCL Version 3 directly, you cannot upgrade to FCL Version 4 until those applications are rewritten to use the new API. The API can interpret both Version 3 and Version 4, so applications can be upgraded to use the API while Version 3 is still in effect.