File system format changes between versions of IBM Spectrum Scale

This topic describes features of IBM Spectrum Scale that operate only with file systems of a particular format level or higher.

Note: The features that are described in this topic are only a subset of the functional changes that are introduced with the different releases of IBM Spectrum Scale. Functional changes that do not require changing the file system format are not listed here. Such changes either are immediately available when the new version of IBM Spectrum Scale is installed, or you need to run the mmchconfig release=LATEST command after the installation.

Every GPFS file system has a format level number that identifies the on-disk format of the file system and is an indicator of the supported file system functions. The file system format number is assigned when the file system is first created and can be updated to the latest supported level when the file system is migrated with the mmchfs -V command.

The format 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 is not enabled until you run the mmchfs -V command. Some new features might require you also to run the mmmigrate command.

Note: The -V parameter cannot be used to create file systems that were created before GPFS 3.2.1.5 available to Windows nodes. Windows nodes can mount file systems only that were created with GPFS 3.2.1.5 or later.
The mmchfs -V parameter 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 that are running an older GPFS version will no longer be able to mount the file system.
    The mmchfs -V full command displays a warning as in the following example:
    # mmchfs n03NsdOnFile36 -V full
    You have requested that the file system be upgraded to
    version 19.01 (5.0.1.0). 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 compatible with an earlier version format changes. Nodes in remote clusters that were able to mount the file system before the format changes can continue to do so afterward.
Start of change
In IBM Spectrum Scale 5.1.2, new file systems are created at file system format level 26.00. To update a file system from an earlier format to format level 26.00, issue the following command:
mmchfs Device -V full
where Device is the device name of the file system. The following feature of IBM Spectrum Scale 5.1.2 requires a file system to be at format number 26.00 or later:
  • Fine-Grained Directory Locking (FGDL) for link. FGDL is enabled to improve performance of link creation when concurrent hard links are created in a single directory from multiple nodes.
End of change
In IBM Spectrum Scale 5.1.1, new file systems are created at file system format level 25.00. To update a file system from an earlier format to format level 25.00, issue the following command:
mmchfs Device -V full
where Device is the device name of the file system. The following features of IBM Spectrum Scale 5.1.1 require a file system to be at format number 25.00 or later:
  • The integrated archive management (IAM) mode support for the AFM-DR filesets.

    On a primary site and the secondary site, the cluster version must be upgraded to the latest version by using the mmchconfig release=LATEST command.

In IBM Spectrum Scale 5.1.0, new file systems are created at file system format level 24.00. To update a file system from an earlier format to format level 24.00, issue the following command:
mmchfs Device -V full
where Device is the device name of the file system. The following features of IBM Spectrum Scale 5.1.0 require a file system to be at format number 24.00 or later:
  • Creating AFM to cloud object storage fileset.
In IBM Spectrum Scale 5.0.5, new file systems are created at file system format level 23.00. To update a file system from an earlier format to format level 23.00, issue the following command:
mmchfs Device -V full
where Device is the device name of the file system. The following features of IBM Spectrum Scale 5.0.5 require a file system to be at format number 23.00 or later:
  • Enabling FastCreate on AFM and AFM-DR filesets.
In IBM Spectrum Scale 5.0.4, new file systems are created at file system format level 22.00. To update a file system from an earlier format to format level 22.00, issue the following command:
mmchfs Device -V full
where Device is the device name of the file system. The following features of IBM Spectrum Scale 5.0.4 require a file system to be at format number 22.00 or later:
  • Support for thin provisioned storage devices and NVMe SSDs.
  • Support for linking GPFS dependent filesets inside AFM and AFM-DR filesets.
In IBM Spectrum Scale 5.0.3, new file systems are created at file system format level 21.00. To update a file system from an earlier format to format level 21.00, issue the following command:
mmchfs Device -V full
where Device is the device name of the file system. The following features of IBM Spectrum Scale 5.0.3 require a file system to be at format number 21.00 or later:
  • Genomic compression
In IBM Spectrum Scale 5.0.2, new file systems are created at file system format number 20.01. To update a file system from an earlier format to format number 20.01, issue the following command:
mmchfs Device -V full
where Device is the device name of the file system. The following features of IBM Spectrum Scale 5.0.2 require a file system to be at format number 20.01 or later:
  • The afmGateway attribute of the mmchfileset command specifies a user-defined gateway node for an AFM or AFM DR fileset that is given preference over the internal hashing algorithm.
  • The maxActiveIallocSegs performance attribute of the mmchconfig command controls the number of active inode allocation segments that are maintained on a node. In IBM Spectrum Scale 5.0.2 and later the default number is 8 and the range is 1 - 64. In earlier versions the default value and also the maximum value is 1.
  • The clustered watch folder feature provides you the ability to watch file operations across clusters. For more information, see Introduction to clustered watch folder.
In IBM Spectrum Scale 5.0.1, new file systems are created at format number 19.01. To update the format of an earlier file system to format number 19.01, issue the following command:
mmchfs Device -V full
where Device is the device name of the earlier file system.
In IBM Spectrum Scale 5.0.0, new file systems are created at format number 18.00. To update the format of an earlier file system to format number 18.00, issue the following command:
mmchfs Device -V full
where Device is the device name of the earlier file system. The following features of IBM Spectrum Scale 5.0.0 require a file system to be at format number 18.00 or later:
  • Smaller subblock sizes for file systems that have a large data block size.
    Note: This feature is supported only for file systems that are created at file system format number 18.00 or later. It is not supported for file systems that are updated to format number 18.00 or later from an earlier format number. For more information, see mmcrfs command.
  • File compression with the lz4 compression library
  • File audit logging
In IBM Spectrum Scale 4.2.3.0, new file systems are created at format number 17.00. To update the format of an earlier file system to format number 17.00, issue the following command:
mmchfs Device -V full
where Device is the device name of the earlier file system. The following features of IBM Spectrum Scale v4.2.3.0 require a file system to be at format number 17.00 or later:
  • Quality of Service for I/O (QoS)
  • File compression with zlib compression library
  • Information lifecycle management (ILM) for snapshots
If your current file system is at format number 14.20 (IBM Spectrum Scale 4.1.1), the set of enabled features depends on the value that is specified with the mmchfs -V option:
  • After running mmchfs -V full, the file system can 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 number 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 can 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 number 13.23 (GPFS 3.5.0.7), the set of enabled features depends on the value that is specified with the mmchfs -V option:
  • After running mmchfs -V full, the file system can support the following:
    • Directory block sizes can be up to 256 KB (previous maximum was 32 KB).
    • Directories can 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 number 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 can support the following:
    • Extended storage pool properties
    • File Placement Optimizer (FPO)
    • Storing small directories in the inode
    • Storing the data for small files in the inode
  • There are no new features that can be enabled with mmchfs -V compat.
If your current file system is at format number 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 can support the following:
    • Independent filesets and snapshots of individual independent filesets
    • Active file management (AFM)
    • 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 number 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 can 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 number 10.00 (GPFS 3.2.0.0) or 10.01 (GPFS 3.2.1.5), after running mmchfs -V, the file system can 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 number 9.03 (GPFS 3.1), after running mmchfs -V, the file system can 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 number 8.00 (GPFS 2.3), after running mmchfs -V, the file system can support all of the features included with earlier levels, plus:
  • Storage pools
  • Filesets
  • Fileset quotas
If your current file system is at format number 7.00 (GPFS 2.2), after running mmchfs -V, the file system can support all of the features that are 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 number 6.00 (GPFS 2.1), after running mmchfs -V, the file system can support all of the features that are included with earlier levels and extended access control list entries (-rwxc access mode bits).