File system format changes between versions of GPFS

Every GPFS™ file system has a format version number associated with it. This version number corresponds to the on-disk data structures of the file system and is an indicator of the supported file system functionality.

The file system version number is assigned when the file system is first created, and is updated to the latest supported level after the file system is migrated using the mmchfs -V command.

The format version number for a file system can be displayed with the mmlsfs -V command. If a file system was created with an older GPFS release, new functionality that requires different on-disk data structures will not be enabled until you run the mmchfs -V command. In addition to mmchfs -V, certain new features may require you to additionally run the mmmigratefs command.

Note: The -V option cannot be used to make file systems created prior to GPFS 3.2.1.5 available to Windows nodes. Windows nodes can mount only file systems that are created with GPFS 3.2.1.5 or later.
The mmchfs -V option requires the specification of one of two values - full or compat:
  • Specifying mmchfs -V full enables all of the new functionality that requires different on-disk data structures. After this command, nodes in remote clusters running an older GPFS version will no longer be able to mount the file system.
    Running the mmchfs -V full gives you a warning similar to the following:
    Warning: 
    # mmchfs n03NsdOnFile36 -V full
You have requested that the file system be upgraded to
version 15.01 (4.2.0.0). This will enable new functionality but will
prevent you from using the file system with earlier releases of GPFS.
Do you want to continue?
  • Specifying mmchfs -V compat enables only features that are backward compatible with nodes running GPFS 3.2. After this command, nodes in remote clusters running GPFS 3.2 or later will still be able to mount the file system, but nodes running GPFS versions 3.1 or older will not be able to mount the file system.
The current highest file system format version is 15.01. This is the version that is assigned to file systems created with IBM Spectrum Scale™ 4.2.0.0. The same version number will be assigned to older file systems after you run the mmchfs -V full command.
  • After running mmchfs -V full, the file system will be able to support the following:
    • Quality of Service (QoS) function is enabled
    • Compression
If your current file system is at format level 14.20 (IBM Spectrum Scale 4.1.1), the set of enabled features depends on the value specified with the mmchfs -V option:
  • After running mmchfs -V full, the file system will be able to support the following:
    • Enabling and disabling of quota management without unmounting the file system.
    • The use of fileset-level integrated archive manager (IAM) modes.
  • There are no new features that can be enabled with mmchfs -V compat.
If your current file system is at format level 14.04 (GPFS 4.1.0.0), the set of enabled features depends on the value specified with the mmchfs -V option:
  • After running mmchfs -V full, the file system will be able to support different block allocation map types on an individual storage-pool basis.
  • There are no new features that can be enabled with mmchfs -V compat.
If your current file system is at format level 13.23 (GPFS 3.5.0.7), the set of enabled features depends on the value specified with the mmchfs -V option:
  • After running mmchfs -V full, the file system will be able to support the following:
    • directory block sizes up to 256 KB (previous maximum was 32 KB)
    • directories will be able to reduce their size when files are removed
  • There are no new features that can be enabled with mmchfs -V compat.
If your current file system is at format level 13.01 (GPFS 3.5.0.1), the set of enabled features depends on the value specified with the mmchfs -V option:
  • After running mmchfs -V full, the file system will be able to support the following:
    • extended storage pool properties
    • File Placement Optimizer (FPO)
  • There are no new features that can be enabled with mmchfs -V compat.
If your current file system is at format level 12.03 (GPFS 3.4), the set of enabled features depends on the value specified with the mmchfs -V option:
  • After running mmchfs -V full, the file system will be able to support the following:
    • independent filesets and snapshots of individual independent filesets
    • active file management (AFM)
    • storing the data for small files in the inode
    • file clones (writable snapshots of a file)
    • policy language support for new attributes, variable names, and functions: OPTS clause for the SET POOL and RESTORE rules, encoding of path names via an ESCAPE clause for the EXTERNAL LIST and EXTERNAL POOL rules, GetEnv(), GetMMconfig(), SetXattr(), REGEX().
  • There are no new features that can be enabled with mmchfs -V compat.
If your current file system is at format level 11.03 (GPFS 3.3), the set of enabled features depends on the value specified with the mmchfs -V option:
  • After running mmchfs -V full, the file system will be able to support the following:
    • more than 2,147,483,648 files
    • fast extended attributes (which requires mmmigratefs to be run also)
  • There are no new features that can be enabled with mmchfs -V compat.
If your current file system is at format level 10.00 (GPFS 3.2.0.0) or 10.01 (GPFS 3.2.1.5), after running mmchfs -V, the file system will be able to support all of the features included with earlier levels, plus the following:
  • new maximum number of filesets in a file system (10000)
  • new maximum for the number of hard links per object (2**32)
  • improved quota performance for systems with large number of users
  • policy language support for new attributes, variable names, and functions: MODE, INODE, NLINK, RDEVICE_ID, DEVICE_ID, BLOCKSIZE, GENERATION, XATTR(), ATTR_INTEGER(), and XATTR_FLOAT()
If your current file system is at format level 9.03 (GPFS 3.1), after running mmchfs -V, the file system will be able to support all of the features included with earlier levels, plus:
  • fine grain directory locking
  • LIMIT clause on placement policies
If your current file system is at format level 8.00 (GPFS 2.3), after running mmchfs -V, the file system will be able to support all of the features included with earlier levels, plus:
  • storage pools
  • filesets
  • fileset quotas
If your current file system is at format level 7.00 (GPFS 2.2), after running mmchfs -V, the file system will be able to support all of the features included with earlier levels, plus:
  • NFS V4 access control lists
  • new format for the internal allocation summary files

If your current file system is at format level 6.00 (GPFS 2.1), after running mmchfs -V, the file system will be able to support all of the features included with earlier levels, plus extended access control list entries (-rwxc access mode bits).

The functionality described in this topic is only a subset of the functional changes introduced with the different GPFS releases. Functional changes that do not require changing the on-disk data structures are not listed here. Such changes are either immediately available when the new level of code is installed, or require running the mmchconfig release=LATEST command. For a complete list, see the Summary of changes.

Parent topic: Administering