Active File Management (AFM) features

The following sections list features of Active File Management (AFM).

Support of linking GPFS dependent fileset
Active File Management (AFM) supports to create and link a dependent fileset inside an independent fileset.
Force flushing contents before Async Delay
Parallel data transfers
Parallel data transfer improves the AFM data transfer performance.
Parallel data transfer using multiple remote mounts
Parallel data transfer by using the multiple remote mounts on the gateway node improves the AFM data transfer performance by sending unique data operations across multiple NFS server mounts.
Partial file caching
With partial file caching, the cache can fetch only the blocks that are read and not the entire file, thereby utilizing network and local disk space more efficiently. This is useful when an application does not need to read the whole file. Partial file caching is enabled on an IBM Spectrum Scale block boundary.
Prefetch
Prefetch fetches the file metadata (inode information) and data from home before an application requests the contents.
Peer snapshot -psnap
The peer snapshot function provides a snapshot at home and cache separately, ensuring application consistency on both sides (cache and home).
Gateway node failure and recovery
When the Primary gateway of a fileset fails, another gateway node takes over the ownership of the fileset.
Cache eviction
Cache eviction is a feature where file data blocks in the cache are released when fileset usage exceeds the fileset soft quota, and space is created for new files.
Operation with disconnected home
With a cache and home cluster separated by a WAN (wide area network), it might result in intermittent outages and possibly long-term disruptions.
Expiring a disconnected RO cache
Read-only filesets can be configured to expire cached data after the gateway nodes are in a disconnected state for a specified amount of time.
Viewing snapshots at home
All snapshots at home for RO and LU filesets can be viewed in the cache by setting the afmShowHomeSnapshot parameter to yes. This variable is not applicable for SW and IW filesets.
Changing home of AFM cache
AFM filesets continue to function in the event of home failures.
Resync on SW filesets
A conflict situation might arise due to an inadvertent write on an SW home. AFM runs a resynchronization automatically.
Using IBM Spectrum Protect for Space Management (HSM)
IBM Spectrum Protect for Space Management (HSM) can be used on the AFM filesets or on the home.
Performing a planned maintenance by using the IW cache
You can perform a planned maintenance by using IW cache.
Handling IW cache disaster
You can perform a planned or unplanned maintenance by using IW cache
Using AFM with encryption
AFM supports file encryption. Encryption can be applied to AFM-managed filesets.
Using mmbackup
When mmbackup is run on a file system that has AFM filesets, only the cached data from the filesets is backed up.
Disabling AFM
An AFM fileset can be disabled and converted to a GPFS-independent fileset. However, GPFS-independent fileset cannot be converted to an AFM fileset.
Stop and start replication on a fileset
The stop and start operations can be used during the downtime planning of the replication activities on an AFM or AFM-DR fileset. When you stop the replication on an AFM fileset, the fileset state changes to 'Stopped' and the replication between both sites stops until you perform the 'start' operation on the stopped fileset. These operations are useful to control the replication during the downtime and manage the bandwidth efficiently.

Parent topic: Active File Management