【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.