AFM Limitations

AFM limitations include:

If you change an AFM SW/IW home export from Kernel NFS or CNFS to the new IBM Spectrum Scale™ CES in 4.1.1 or later, AFM will not recognize the home. The best way to manage this situation is to run the mmafmctl failover command. See the IBM Spectrum Scale documentation for more details.
AFM RO/LU home export cannot be changed from Kernel NFS or CNFS to new Spectrum Scale CES in 4.1.1. or later.
Customers who have enabled DMAPI/HSM at the AFM home cluster should be running at RHEL 6.3, or later, or SLES 11 SP2, or later, on the cache cluster. There has been a bug identified in earlier levels of RHEL which requires that the exported path at home be excluded from DMAPI/HSM. See http://www-01.ibm.com/support/docview.wss?uid=ssg1S1004310 .
Code upgrade limitations:
- If there are AFM filesets using the Kernel NFS backend to communicate with a GPFS™ home that is running V4.1 or earlier, upgrading home to IBM Spectrum Scale V4.1.1 or later will cause the AFM filesets to disable synchronization to home with a message as follows:
```
GPFS: 6027-3218 Change in home export detected. Synchronization with home 
is suspended until the problem is resolved
```
  Note: This only affects AFM filesets that were originally created with a GPFS home running V4.1 or earlier. This does not affect AFM filesets that were created with a home running IBM Spectrum Scale V4.1.1 or later. This issue is fixed in 4.1.1.4 and 4.2.0.1 available at Fix Central (IBM® Fix central).
AFM filesets do not support the gpfs API - gpfs_prealloc.