Supported Features of the Kernel Driver

The kernel driver is developed separately from the core ceph code, and assuch it sometimes differs from the FUSE driver in feature implementation.The following details the implementation status of various CephFS featuresin the kernel driver.

Inline data

Inline data was introduced by the Firefly release. This feature is beingdeprecated in mainline CephFS, and may be removed from a future kernelrelease.

Linux kernel clients >= 3.19 can read inline data and convert existinginline data to RADOS objects when file data is modified. At present,Linux kernel clients do not store file data as inline data.

See Experimental Features for more information.

Quotas

Quota was first introduced by the hammer release. Quota disk format got renewedby the Mimic release. Linux kernel clients >= 4.17 can support the new formatquota. At present, no Linux kernel client support the old format quota.

See Quotas for more information.

Multiple file systems within a Ceph cluster

The feature was introduced by the Jewel release. Linux kernel clients >= 4.7can support it.

See Experimental Features for more information.

Multiple active metadata servers

The feature has been supported since the Luminous release. It is recommended touse Linux kernel clients >= 4.14 when there are multiple active MDS.

Snapshots

The feature has been supported since the Mimic release. It is recommended touse Linux kernel clients >= 4.17 if snapshot is used.