What is a Storage Processor ?

The main component in all CLARiiON series arrays is the Storage Processor. Storage Processors (SPs) are configured in pairs for maximum availability and are Field Replaceable Units (FRUs). SPs provide both front-end connectivity to the hosts and back-end connectivity to the physical disks. Each Storage Processor also includes up to 4 GB of memory, most of which is used for cache. Cache memory is segmented into read cache memory and write cache memory. Read cache memory is used for staging and prefetching read requests from the host. Write cache is used to accelerate host writes to the storage system. 

With write cache enabled, writes are mirrored to the write cache memory in the other storage processor over the CLARiiON Messaging Interface (CMI). The CMI is a Fibre Channel based link and operates at either 100MB/sec on FC series or 200MB/sec on CX series systems. Each storage processor also includes a TCP/IP connection that is used for configuration and management of the storage system.Each storage system ships with a complete copy of FLARE software installed on the first four disks on back-end loop 0. Disks 0_0 and 0_2 store mirrored copies of the software for SP A, and disks 0_1 and 0_3 store mirrored copies of the software for SP B. When you power up the storage system, each SP boots and executes FLARE software.

Salient Features :-

# Storage processors are configured in pairs for maximum availability.

# One or two processors per Storage Processor board.

# Two or four Fibre Channel front-end ports for host connectivity

– 1Gb or 2Gb.

– Arbitrated loop or switched fabric.

# Dual-ported Fibre Channel Disk drives at the back-end.

– Two or Four Arbitrated Loop connections.

# Maximum of 4GB of memory per SP.

– Write Cache is mirrored between Storage Processors for availability using the CMI 

(CLARiiON Messaging Interface)

– Write Caching accelerates host writes.

# Ethernet connection for management.