Known Limitations

Volume and Pool Capacity Expansion

Once provisioned, neither Mayastor Disk Pools nor Mayastor Volumes can be re-sized. A Mayastor Pool can have only a single block device as a member. Mayastor Volumes are exclusively thick-provisioned.

Snapshots and Clones

Mayastor has no snapshot or cloning capabilities.

Volumes are "Highly Durable" but without multipathing are not "Highly Available"

Mayastor Volumes can be configured (or subsequently re-configured) to be composed of 2 or more "children" or "replicas"; causing synchronously mirrored copies of the volumes's data to be maintained on more than one worker node and Disk Pool. This contributes additional "durability" at the persistence layer, ensuring that viable copyies of a volume's data remain even if a Disk Pool device is lost.

However a Mayastor volume is currently accessible to an application only via a single target instance (NVMe-oF, or iSCSI) of a single Mayastor pod. If that pod terminates (through the loss of the worker node on which it's scheduled, execution failure etc.) then there will be no viable I/O path to any remaining healthy replicas and access to data on the volume cannot be maintained. Mayastor will try to create the nexus on the same node where the application will be running if possible. That avoids the problem of nexus being inaccessible for the application if the node is down. See "local" storage class parameter description for more in-depth explanation.

There has been initial discovery work completed in supporting and testing the use of multipath connectivity to Mayastor pods. The work of developing and supporting production usage of multipath connectivity is currently scheduled to complete after general availability.