High Available Storage Systems (HASS) provide two internal
SCSI busses, each with their own connectors, power cords, power
supplies, and fans. This hardware redundancy, when combined with
software mirroring, can prevent most single point of failure problems.
HASS do not provide any RAID support on their own.
Pros and
Cons of HASS |
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There are many advantages of systems protected by HASS. These include
disk storage modules that are hot-pluggable which
means that the bus and connectors are made so that the disk module
can be inserted or removed without removing the terminator for the
array. All hardware modules are easily removed from the front of
the chassis. HASS do not have the problems of previous disk configurations
that required extra-long F/W SCSI cables, the removal of the chassis
from the cabinet, and the removal of the cover before individual
disk mechanisms can be replaced.
The negative side of HASS is that operating system cooperation
is still required when removing a disk module from the HASS since
the HASS does not provide any data protection
or regeneration of data on a newly replaced disk module. HASS is
primarily a hardware protection strategy and software mirroring
is required to implement a mirroring scheme on HASS.
Recommended
Uses of HASS |
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The HASS protection system is an excellent step in preventing
single points of failure and is recommended for systems that must
be available as much of the time as possible. Serviceguard can employ
HASS for additional data storage. See“Using Serviceguard”.
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