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PCI
Controlled RAID Solutions
This
solution is a usually a hybrid between software based solutions
and dedicated hardware based solutions. The PCI RAID controller
doubles as both the SCSI host controller and caching processor all
combined onto one PCI board with a software based administration
programme running on the system it is installed into. This solution
is usually only found in systems running Microsoft Windows (NT,
Win9x, Win2000), NetWare, and Macintosh operating systems.
Many PCI-based solutions make excellent entry-level systems and
still provide a much higher level of data protection than any single
drive storage solutions. Nearly all require the use of SCSI drives
which also adds additional performance benefits.
Advantages:
Takes I/O requests from main CPU and performs all RAID parity
calculations independently of the system software. This vastly reduces
the overhead present in pure software solutions. Integrated SCSI
controller handles specific addressing of target drives and read/writes
to and from the physical disks with no further system intervention.
On-board memory acts as a large cache for I/O operations producing
even further performance benefits.
Disadvantages:
Still reliant on host running administration control software to
provide RAID facilities. The RAID controller processor is embedded
onto the board itself but requires drivers from the administration
software to initialise and use the array. If the host fails, the
card must be installed onto another host and the control software
installed before data is accessible once more.
Related
topics:
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