12.3. Tiering Limitations

The following limitations apply to the use Tiering feature:

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.
In this release, only Fuse and NFSv3 access is supported. Server Message Block (SMB) and NFSv4 access to tiered volume is not supported.
Snapshot clones are not supported with the tiered volumes.
When you run tier detach commit force, ongoing I/O operation may fail with 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 10.3.1, “Expanding a Tiered Volume” and for information on shrinking a tiered volume, see Section 10.4.2, “Shrinking a Tiered Volume ”