Hitachi 9900 Series, 9960 Hitachi Data Systems, Mirrored cache instead of single image cache.1

Hitachi Data Systems

Bus contention is virtually eliminated with the Hi-Star™Architecture.

Figure 3 – System block diagram of the 7700E’s shared bus architecture.

Hitachi is the only major supplier of enterprise class storage systems with a 100% availability guarantee.

Comparison to the Shared Bus Architecture of the Hitachi Freedom Storage™ 7700E

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™ has an advanced availability profile compared to competitive products

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.

1Some 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.

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