Hitachi 9900 Series - Manual (Page 38)

Hitachi High Availability Software Improves Application Service Levels
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Standard Redundant Fans for Cooling
The Lightning 9900 ™ provides fully redundant fans for uninterrupted cooling to all
components of the system. The speed and operation of these fans are monitored by the
environmental monitoring system. If a fan should fail, it can be “hot swapped” without
disruption to the cooling system.
Unmatched Competitive Advantage in RAID Choices
The flexibility in choice for Lightning 9900 ™ Series RAID protection for disk drives is
unmatched. It is important to have choices in RAID protection since files and data have
different characteristics in terms of user required performance, uptime, and rebuild times.
RAID-1+ (mirroring) offers the highest performance (read from either disk in the mirror
pair) during normal operation. RAID-1+ also offers the highest performance in the event
of a failed disk since it is not necessary to read parity (and then data) in the event of a disk
failure in other RAID configurations.
The Lightning 9900 ™ Series also offers the capability to intermix RAID levels within a
system, depending on the level of availability and performance required by the data hosted
on the Lightning 9900
™ Series system. For example, a single Lightning 9900 ™ Series system
can configure both RAID-1+ and RAID-5.