Specifications

Escala Tower PL & S, E, T System Hardware
Chapter 3: External Storage and SAN Subsystems 35/116
9es3s1c3.doc
Rev 5.9
02/12/2003
The major components of the 1000, 2000 and 3000 Series are:
•
Storage-Control Processor (SP) with optional single or mirrored cache memory
•
Disk modules (3.5" SCSI-2, high performance, single ended drives)
•
Disk array cabinet (10 drives chassis for DAS1300, 20 drives chassis for DAS2900, and 30 drives
chassis for DAS3200/DAS3500)
•
Redundant power subsystem
•
Redundant cooling subsystem
•
Battery Backup Unit for cache security
3.2. The Storage Control Processor (SP)
The Storage Control Processors (SP) are the main components of the DAS1300, DAS2900 and
DAS3200/DAS3500. One or two SPs can be configured in a disk array cabinet. The DAS1300 Storage
Processor design is based on a 25MHz AMD 29000 RISC processor, 4MB of instruction and data
memory, three or six SCSI-2 interface controllers, power regulator, and RS232 interface. The new
DAS2900 and DAS3200/DAS3500 Storage Processor is based on Power PC technology, with a basic
8 MB memory.
The Storage Control Processor serves a number of functions including the RAID 0, 1, 1/0, 3, and 5
modes of operation, as well as individual disk operation. The SP continuously monitors the status of
the other major components concurrently with the temperature within the storage subsystem and
notifies the host in the event of a failure.
The DAS 1000, 2000 and 3000 Series are optimized to provide high I/O throughput in server
environments. They can support two Storage Control Processors (dual active) within the same cabinet.
Dual active SPs induce higher overall I/O performance by minimizing bus contention and paralleling
data access.
The two SPs can be interfaced directly to a host resident SCSI-2 adapter (or Fibre Channel Adapter for
the DAS3500) or daisy chained on the SCSI bus. Each SP is configured as a unique SCSI ID and can
support up to 32 logical units (LUNs) each. A LUN would be equivalent to a RAID stripe. The disk
drives within the array can be logically connected to any of the Storage-Control Processors. However,
dynamically shared access to a drive group is not supported.
In the event of an SP failure, access to data is insured due to the dual-ported subsystem architecture
with active dual initiator. The SP can house a modular memory for write cache option.