Storage Backends¶

StarlingX supports an internal Ceph block storage backend and connecting to an external Netapp Trident block storage backend. Configuring a storage backend is optional, but it is required if the applications being hosted require persistent volume claims (PVCs).

Internal Ceph¶

StarlingX can be configured with an internal Ceph storage backend on StarlingX controller nodes or on dedicated StarlingX storage nodes.

You can organize the OSDs in the hosts into tiers with different performance characteristics such as SATA, SAS, SSD and NVME.

The following internal Ceph deployment models are supported:

Table 1. Internal Ceph Deployment Models¶
Name	Description
storage-nodes	Applies to the Standard with Dedicated Storage deployment configuration. Storage nodes are deployed in replication groups of 2 or 3, depending on the configured replication factor. Ceph OSDs are configured only on storage nodes. Ceph monitors are automatically configured on controller-0, controller-1 and storage-0. Data replication is done between storage nodes within a replication group. After configuring a storage node, OSDs cannot be added to controllers.
controller-nodes	Applies to the Standard with Controller Storage and the All-in-One Duplex deployment configurations. Ceph OSDs are configured on controller nodes. For All-in-One Duplex configurations, a single Ceph monitor is automatically configured that runs on the ‘active’ controller. For Standard with Controller Storage, Ceph monitors are automatically configured on controller-0 and controller-1, and a third must be manually configured by user on a worker node. Data replication is done between controllers. After configuring an OSD on a controller, storage nodes cannot be installed.
aio-sx	Applies to All-in-One Simplex deployment configurations. Ceph OSDs are configured on controller-0. A single Ceph monitor is automatically configured on controller-0. Replication is done per OSD, not per node. Configuration updates are applied without requiring a host lock/unlock. You can set replication to 1, 2 or 3 (default is 1). A replication setting of 1 requires a minimum of one OSD. A replication setting of 2 requires a minimum of two OSDs to provide data security. A replication setting of 3 requires a minimum of three OSDs to provide data security. When replication 2-3 is set, data is replicated between OSDs on the node.

For more information on Ceph storage backend provisioning, see Configure the Internal Ceph Storage Backend.

External Netapp Trident¶

StarlingX can be configured to connect to and use an external Netapp Trident deployment as its storage backend.

Netapp Trident supports:

AWS Cloud Volumes
E and EF-Series SANtricity
ONTAP AFF, FAS, Select, and Cloud
Element HCI and SolidFire
Azure NetApp Files service

For more information about Trident, see https://netapp-trident.readthedocs.io.