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.
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.
- 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.
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.
mmchfs Device -V full
where
Device is the device name of the file system. The following feature of IBM
Spectrum Scale 5.1.1 requires 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.
mmchfs Device -V full
where
Device is the device name of the file system. The following feature of IBM
Spectrum Scale 5.1.0 requires a file system to be at format
number 24.00 or later:- Creating AFM to cloud object storage fileset.
mmchfs Device -V full
where
Device is the device name of the file system. The following feature of IBM
Spectrum Scale 5.0.5 requires a file system to be at format
number 23.00 or later:- Enabling FastCreate on AFM and AFM-DR filesets.
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.
mmchfs Device -V full
where
Device is the device name of the file system. The following feature of IBM
Spectrum Scale 5.0.3 requires a file system to be at format
number 21.00 or later:- Genomic compression
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.
mmchfs Device -V full
where
Device is the device name of the earlier file system.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
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
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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()
- fine grain directory locking
- LIMIT clause on placement policies
- Storage pools
- Filesets
- Fileset quotas
- 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).