Subsystem Scalability - Hitachi 9900 User And Reference Manual

1.1.7

Subsystem Scalability

The architecture of the 9900 subsystem accommodates scalability to meet a wide range of
capacity and performance requirements. The 9960 storage capacity can be increased from a
minimum of 54 GB to a maximum of 88 TB of user data. The 9960 nonvolatile cache can be
configured from 1 GB to 32 GB. All disk drive and cache upgrades can be performed without
interrupting user access to data.
The 9900 subsystem can be configured with the desired number and type of front-end client-
host interface processors (CHIPs). The CHIPs are installed in pairs, and each CHIP pair offers
up to eight host connections. The 9960 can be configured with four CHIP pairs to provide up
to 32 paths to attached host processors. The 9910 supports up to three CHIP pairs and 24
paths.
The ACPs are the back-end processors which transfer data between the disk drives and
cache. Each ACP pair is equipped with eight device paths. The 9960 subsystem can be
configured with up to four pairs of array control processors (ACPs), providing up to thirty-
two concurrent data transfers to and from the disk drives. The 9910 is configured with one
ACP pair.
8 Chapter 1 Overview of the Lightning 9900™ Subsystem