Veritas™ File System Programmer's Reference Guide - Solaris

Last Published:
Product(s): InfoScale & Storage Foundation (7.2)
Platform: Solaris
  1. Veritas File System software developer's kit
    1.  
      About the software developer's kit
    2. File System software developer's kit features
      1.  
        API library interfaces
      2.  
        File Change Log
      3.  
        Multi-volume support
      4.  
        Veritas File System I/O
    3.  
      Software developer's kit packages
    4.  
      Required libraries and header files
    5. Compiling environment
      1.  
        Recompiling with a different compiler
  2. File Change Log
    1. About the File Change Log file
      1.  
        Recorded changes
      2. Using the File Change Log file
        1.  
          Space usage
        2.  
          Full system scan reductions
        3.  
          File history traces
      3.  
        File Change Log logging activation
      4. File Change Log file layout
        1.  
          File Change Log superblock
        2.  
          File Change Log record
    2. Record types
      1.  
        Special records
      2.  
        Typical record sequences
    3. File Change Log tunables
      1.  
        How tunables handle File Change Log growth size
    4. Application programming interface for File Change Log
      1.  
        Ease of use
      2.  
        Backward compatibility
      3. API functions
        1.  
          Functions for accessing File Change Log records
        2.  
          Functions for seeking offsets and time stamps in the File Change Log
        3. vxfs_fcl_open
          1.  
            Return value
        4. vxfs_fcl_close
          1.  
            Parameters
        5. vxfs_fcl_getinfo
          1.  
            Return values
        6. vxfs_fcl_read
          1.  
            Parameters
          2.  
            Input
          3.  
            Output
          4.  
            Return values
        7. vxfs_fcl_getcookie
          1.  
            Parameters
        8. vxfs_fcl_seek
          1.  
            Parameters
          2.  
            Return values
        9. vxfs_fcl_seektime
          1.  
            Parameters
          2.  
            Return values
        10. vxfs_fcl_sync
          1.  
            Parameters
      4. File Change Log record
        1.  
          Defines
        2.  
          fcl_iostats structure
        3.  
          fcl_acsinfo structure
        4.  
          Record structure fields
      5. Copying File Change Log records
        1.  
          Index maintenance application
        2. Computing a usage profile
          1.  
            Initial setup
          2.  
            Sample steps
          3.  
            Off host processing
      6. Veritas File System and File Change Log upgrade and downgrade
        1.  
          Converting File Change Log version 3 files to version 4
        2.  
          Downgrading Veritas File System versions
    5. Reverse path name lookup
      1.  
        Inodes
      2.  
        vxfs_inotopath_gen
  3. Multi-volume support
    1.  
      About multi-volume support
    2.  
      Uses for multi-volume support
    3. Volume application programming interfaces
      1.  
        Administering volume sets
      2.  
        Querying the volume set for a file system
      3.  
        Modifying a volume within a file system
      4.  
        Encapsulationg and de-encapsulating a volume
    4. Allocation policy application programming interfaces
      1.  
        Directing file allocations
      2.  
        Creating and assigning policies
      3.  
        Querying the defined policies
      4.  
        Enforcing a policy
    5.  
      Data structures
    6. Using policies and application programming interfaces
      1.  
        Defining and assigning allocation policies
      2.  
        Using volume application programming interfaces
  4. Named data streams
    1.  
      About named data streams
    2.  
      Uses for named data streams
    3.  
      Named data streams application programming interface
    4.  
      Listing named data streams
    5.  
      Namespace for named data streams
    6.  
      Behavior changes in other system calls
    7.  
      Querying named data streams
    8.  
      Application programming interface
    9.  
      Command reference
  5. Veritas File System I/O
    1.  
      About Veritas File System I/O
    2.  
      Freeze and thaw
    3. Caching advisories
      1.  
        Direct I/O
      2.  
        Concurrent I/O
      3.  
        Unbuffered I/O
      4.  
        Other advisories
    4. Extents
      1. Extent attributes
        1.  
          Attribute specifics
      2.  
        Reservation: preallocating space to a file
      3.  
        Fixed extent size
      4.  
        Application programming interface for extent attributes
      5. Allocation flags
        1.  
          Allocation flags with reservation
        2.  
          Reservation trimming
        3.  
          Non-persistent reservation
        4.  
          No write beyond reservation
        5.  
          Contiguous reservation
        6.  
          Include reservation in the file size
        7.  
          Reading the grown part of the file
      6.  
        Allocation flags with fixed extent size
      7.  
        How to use extent attribute APIs
      8.  
        Setting fixed extent size
  6. Thin Reclamation
    1.  
      About Thin Storage
    2.  
      About Thin Reclamation
    3. Thin Reclamation application programming interface
      1.  
        vxfs_ts_reclaim return values

File Change Log file layout

In VxFS 4.1, the internal layout of the FCL file was exposed to the user and the applications were expected to access the FCL file using standard file system interfaces, such as open(2), read(2), and lseek(2). However, this methodology may lead to future compatibility issues, because if the underlying FCL layout and the FCL version changes, the application must be changed and recompiled to accommodate these changes.

VxFS 5.0 introduced a new programming interface that provides improved compatibility, even when the on-disk FCL layout changes. With this API, the FCL layout is not a concern for applications. Consequently, this section provides only a rudimentary description of the FCL layout.

The FCL file is usually a sparse file containing the FCL superblock and the FCL records. The first information block in the FCL file is the FCL superblock. This block may be followed by an optional hole as well as the FCL records which contain information about the changes in the file system.

Figure: FCL file format depicts the FCL file format.

Figure: FCL file format

FCL file format