Dot Hill Systems II 200 FC service manual Data Availability, Scalability

A fabric switch functions as a routing engine, which actively directs data transfers from source to destination and arbitrates every connection. Bandwidth per node via a fabric switch remains constant when more nodes are added, and a node on a switch port uses a data path with speed up to 100 Mbps to send or receive data.

1.4.4Data Availability

Data availability is one of the major requirements for today’s mission-critical applications. Highest availability can be accomplished with the following functionality:

■Hot-plug capabilities

With proper hardware and software configuration in dual-controller mode, a failed controller can be replaced online while the existing controller is actively serving I/O.

■Dual-loop configurations

Dual loop provides path redundancy and greater throughput.

■Controller communications over Fibre Channel

■This option is selectable either through dedicated loops or all drive loops. It allows a more flexible configuration of redundant controllers.

1.4.5Scalability

The Fibre Channel architecture brings scalability and easier upgrades to storage. Storage expansion can be as easy as cascading another expansion unit to a configured RAID array without powering down the running system. The maximum number of expansion units supported by a single SANnet II 200 Fibre Channel or SATA array is:

■Up to eight SANnet II 200 FC expansion units connected to a SANnet II 200 FC array.

■Up to five SANnet II 200 SATA expansion units connected to a SANnet II 200 SATA array.

■Up to five SANnet II 200 FC expansion units and SANnet II 200 SATA expansion units, in any combination, can be connected to a SANnet II 200 FC RAID array.

Note – The SANnet II 200 SATA SE array does not support expansion units.

Up to 125 devices can be configured in a single FC loop. By default, the array provides two drive loops and four host loops, and operates in Fibre Channel-Arbitrated Loop (FC-AL) and fabric topologies.

Chapter 1 Product and Architecture Overview 1-13