Hitachi 9900 User Manual

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The Lightning 9900 V Series 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.

The flexibility in choice for Lightning 9900 V 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 V 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 V Series system. For example, a single Lightning 9900 V
Series system can configure both RAID-1+ and RAID-5.

With the Lightning 9900 V Series flexible LUN configuration feature, the user can

select LUN sizes as small as 46MB or as large as almost 2TB (using LUSE).