Hitachi 9900 Series User Manual

Unlike the shared common bus architecture of previous generation storage products,

such as the 7700E (as shown in Figure 3 for reference to a shared bus architecture),
Hi-Star

™

is designed to truly scale in both capacity and performance. This is possible only

with the Lightning 9900

™

Series’ internally switched architecture which, unlike shared bus

architectures, does not have to contend for limited bus bandwidth.

The Lightning 9900

™

was designed with maximum emphasis on high availability

computing for today’s most critical enterprises. Figure 15 highlights some of the many
advantages in high-availability design that the Lightning 9900

™

has over competitive

products. 

•   Active dual-ported disk drives instead of single-port active drives.

•   Separate storage for control & configuration tables.

•   Mirrored cache instead of single image cache.

1

•   Hitachi Data Systems is the leading supplier of storage systems for GDPS        

production sites.

•

NanoCopy

™

is a superior scheme for disaster recovery.

•   High-availability, custom designed disk drives.

4

1

Some competitive products do not have dual cache like the Hitachi Lightning 9900

™

. If there

is an unrecoverable error in cache, there is no duplicate backup copy. With these products
there is an increased risk of lost data, especially if the loss occurs in the hardware status
area. The Lightning 9900

™

does not have this problem since all status areas and write data

are duplexed. Although a minor concern to some given the low probability of occurrence, the
thought of data loss is never comforting to enterprise executives charged with 7x24
operations.