AFM DR Limitations

AFM DR Limitations include:
  • Our initial feedback from the field suggests that success of a disaster recovery solution depends on administration discipline, including careful design, configuration and testing. Considering this, IBM® has decided to disable the Active File Management- based Asynchronous Disaster Recovery feature (AFM DR) by default and require that customers deploying the AFM DR feature first review their deployments with IBM Spectrum Scale™ development. You should contact Spectrum Scale Support at scale@us.ibm.com to have your use case reviewed. IBM will help optimize your tuning parameters and enable the feature. Please include this message while contacting IBM Support.
    Note: This limitation does not apply to base AFM support. This applies only to Async DR available with the IBM Spectrum Scale Advanced Edition V4.1.1 and later.
    Have this information available when requesting a development led feasibility assessment for Async DR related proposals.
    • Detailed use case description including any application description for applications running in DR filesets.
    • Network latency and bandwidth between sites.
    • Scale of the solution including the number of filesets, number of files, type of files (small or large), any special file usage (clones or encryption).
    • RPO time.
    • Rate of change of data that needs to be transferred between two RPOs from Async DR primary site to secondary.
    • Number of Async DR filesets.
    • Any plans to use snapshots in Async DR filesets.
  • If you change an AFM DR Secondary export from Kernel NFS or CNFS to the new IBM Spectrum Scale CES in 4.1.1 or later, AFM will not recognize the secondary. The best way to manage this situation is to run the mmafmctl changeSecondary command. See the IBM Spectrum Scale documentation for more details.
  • DR administration using the mmafmctl command is not supported when run from the AIX® OS.
  • AFM ADR (primary/secondary filesets) is not supported on an FPO enabled system.
  • AFM features such as revalidation, eviction, prefetch, show home snapshots, partial file caching, expire and unexpire, mmafmctl resync and failover, and IW failback are not applicable for AFM DR filesets.
Parent topic: AFM-based Asynchronous Disaster Recovery (AFM DR)