Hitachi STORAGE 9900 - Manual (Page 35)

Hitachi Freedom Storage ™
Lightning 9900 ™ V Series
Availability Is Highest in the
Industry
An Overview of High-availability (HA) Computing Software
It is increasingly important for a business to support continued access to global
information 24/7. What’s more, careers often depend on the availability of service levels
provided by IT to the enterprise.
In computer science, availability refers to the degree to which a system or resource is
capable of performing its normal function. Availability is measured in terms of Mean Time
Between Failure (MTBF) divided by MTBF plus the Mean Time to Repair (MTTR).
• AVAILABILITY = MTBF / (MTBF+MTTR)
For example, a server that fails on average once every 5,000 hours and takes an average
of two hours to diagnose, replace faulty components, and reboot, would have an availability
rating of 5,000/(5,000 + 2) = 99.96%. This would correspond to a Level 3 rating using the
Scale of 9s.
S o f t w a re Products Contribute to High-availability Computing
Many factors can cause unplanned downtime. The Hitachi Freedom Storage ™
Lightning 9900 ™ V Series has been designed to eliminate as many of these factors as
possible in hardware redundancy, online replaceable components, and software data copy
functions. This allows copies of data at other locations either locally or remotely so that
processing can continue in the event of an outage.
Backup and restore procedures and products also contribute dramatically to computer
system availability by reducing the time to restore operations in the event of an outage.
Hitachi has teamed with industry-leading storage management software providers, such
as VERITAS ® Software, to provide world-class high-availability solutions. These solutions
contribute to the fact that customers and analysts alike regard Hitachi Freedom Storage
systems as having the highest availability in the industry.
The Lightning 9900 V Series Has an Advanced Availability Profile Compared to
Competitive Pro d u c t s
The Lightning 9900 V Series was designed with maximum emphasis on high-
availability computing for today’s most critical enterprises, including:
• System microcode that can be upgraded nondisruptively
3
• Active/active dual-ported disk drives instead of single-port drives or active/passive
dual-ported drives
• Redundant active components throughout the system, combined with automatic
failover architecture
25
7
Customers and analysts
alike regard Hitachi
Freedom Storage systems
as having the highest
availability in the
industry.
Availability refers to the
degree to which a system
or resource is capable of
performing its normal
function.
3 With the exception of Seagate ® HDD microcode.