IBM Storage TS7785 system components
The TS7785 consists of several primary components that can be described in terms of their system role or according to their technical functions.
Nodes, Clusters, and Grid
The TS7785 uses a distributed node architecture with two node roles: virtualization (vNode) and hierarchical data storage management (hNode).
The vNode presents virtual libraries and drives to the host system.
Virtual cartridges created or updated by the host reside in disk cache or, when Cloud Storage Tier is enabled, in a configured cloud object storage tier such as IBM Storage Deep Archive.
The hNode manages how those virtual cartridges are stored across cache and cloud tiers.
Based on the node architecture, a vNode or hNode can run on separate virtualization hardware or be combined to run on the same hardware. When a vNode and hNode are combined to run on the same virtualization hardware, they are referred to collectively as a General Node, or gNode. The TS7785 runs a gNode. See Figure 1 for an illustration of the relationship between nodes.
The TS7785 Cluster combines the TS7785 server with a disk subsystem, the TS7785 cache controller. This architecture permits additional disks or nodes to be added in future offerings to expand the capabilities of the system. Figure 2 displays a TS7785 configured as a cluster.
The TS7785 Grid, or grid configuration, consists of one or more clusters that are connected to one another to form a high availability or disaster recovery solution. Virtual cartridge attributes and data are replicated across the clusters in a grid to ensure the continuation of production work, should a single cluster become unavailable.
A virtual cartridge can be accessed from any virtual tape drive in the system, even if the virtual cartridge has only a single replica. Should a failure occur at the source cluster, replicated virtual cartridges are still available since any data that is replicated between the clusters is accessible through any other cluster in a grid configuration. Each copy is a valid source of the virtual cartridge. A grid configuration looks like a single storage subsystem to the hosts attached to the clusters; it can be described as a composite library with underlying distributed libraries.
A TS7785 Grid can be created by using TS7785 Clusters.
Multiple TS7785 Grids can be attached to the same host system yet operate independent of one another.