【Hitachi】 A-6541 Disk Array Units

Hitachi’s A-6541, announced in July 1998, was a disk array subsystem that offered high availability, high performance, and high reliability for large-scale open systems.
By revamping the disk array controller, the heart of a disk array unit, with a high-performance processor and a larger cache memory, Hitachi was able to increase the random access performance by nearly three times over the previous A-6533 model and elevate the maximum storage to 2.1 terabytes (when mounted in a dedicated rack). The A-6541 also cut the labor and costs of connecting the unit, even when configuring large-scale cluster systems, by increasing the number of host connection ports. And for greater availability and reliability, the A-6541 featured online maintenance of all major replaceable components and enhanced management functions, such as remote configuration, fault monitoring, and service information alerts.

Features of the A-6541:
  • (1)By using a faster processor and expanding the cache memory size (up to 2 GB per controller), Hitachi raised the random I/O performance nearly three times and the sequential I/O performance nearly 2.5 times.
  • (2)The A-6541 supported the Ultra-2 SCSI host interface as well as the Ultra SCSI and fiber channels. The maximum data transfer speed was 80 MB per second.
  • (3)With more host interface ports, it was possible to directly connect the rack-mounted version to eight servers via SCSI or four servers via fiber.
  • (4)The rack-mounted version featured two spare disks instead of one. The extra spare disk and the dynamic spare disk function gave the subsystem dramatically higher reliability.
Specifications of the A-6541
Enclosure type Cabinet Vertical rack mount Horizontal rack mount
Single unit One rack Single unit One rack
Model name A-6541-CK A-6541-RK RKx2 A-6541-RKY Four RKYs
Host interface fiber channels,Ultra-2 SCSI,Ultra SCSI
Disk drives 4.1GB/8.7GB/17.8GB/35.7GB disk drives
Subsystem capacity 8.3 — 572.2GB 16.6 — 858.4GB 1716,8GB
16.6 — 858.4GB 3433.6GB
Cache size 32 — 1024MB 32 — 2048MB 8GB
32 — 2048MB 16GB
External dimensions [mm]
(w x d x h)