16.3. Tiering Limitations (Deprecated)


Tiering is considered deprecated as of Red Hat Gluster Storage 3.5. Red Hat no longer recommends its use, and does not support tiering in new deployments and existing deployments that upgrade to Red Hat Gluster Storage 3.5.3.
The following limitations apply to the use Tiering feature:
  • Native client support for tiering is limited to Red Hat Enterprise Linux version 6.7, 6.8 and 7.x clients. Tiered volumes cannot be mounted by Red Hat Enterprise Linux 5.x clients.
  • Tiering works only with cache friendly workloads. Attaching a tier volume to a cache unfriendly workload will lead to slow performance. In a cache friendly workload, most of the reads and writes are accessing a subset of the total amount of data. And, this subset fits on the hot tier. This subset should change only infrequently.
  • Tiering feature is supported only on Red Hat Enterprise Linux 7 based Red Hat Gluster Storage. Tiering feature is not supported on Red Hat Enterprise Linux 6 based Red Hat Gluster Storage.
  • Only Fuse and gluster-nfs access is supported. Server Message Block (SMB) and nfs-ganesha access to tiered volume is not supported.
  • Creating snapshot of a tiered volume is supported. Snapshot clones are not supported with the tiered volumes.
  • When you run tier detach commit or tier detach force, ongoing I/O operations may fail with a Transport endpoint is not connected error.
  • Files with hardlinks and softlinks are not migrated.
  • Files on which POSIX locks has been taken are not migrated until all locks are released.
  • Add brick, remove brick, and rebalance operations are not supported on the tiered volume. For information on expanding a tiered volume, see Section 11.7.1, “Expanding a Tiered Volume” and for information on shrinking a tiered volume, see Section 11.8.2, “Shrinking a Tiered Volume ”