Acer SmartRAID V Bedienungsanleitung Seite 174

  • Herunterladen
  • Zu meinen Handbüchern hinzufügen
  • Drucken
  • Seite
    / 256
  • Inhaltsverzeichnis
  • FEHLERBEHEBUNG
  • LESEZEICHEN
  • Bewertet. / 5. Basierend auf Kundenbewertungen
Seitenansicht 173
7-6
Theory of Operation
Hardware RAID Processor DPTs P
3
architecture is based on a new
DPT-exclusive ASIC. This specially designed integrated circuit provides
memory-to-memory and disk-to-memory data transfers that are fully
concurrent with controller CPU execution. Depending on whether the
PCI bus is 32-bit or 64-bit, data transfers occur at 132 or 264 MB/sec data
rates, respectively. Independent DMA and XOR processors execute
Scripts-based programs, enabling DMA and XOR tasks to be chained
and executed without the intervention of the controller CPU. The
hardware RAID processor also generates 128-bit parallel error-
correcting code (ECC) for the controller cache memory. This powerful
ECC is capable of correcting an error of up to 32 bits for each 512-byte
block of data.
Intelligent Caching Because most popular operating systems are
heavily cached, a SmartRAID V controller does not cache data read by
the host. Instead, the controller cache is used for predictive and write-
back caching and provides groups write data for efficient RAID 5
operation. For those environments where read caching on the controller
will improve performance (particularly those without software disk
caching), read caching can be enabled using Storage Manager.
SmartRAID V controllers also incorporate predictive caching
algorithms. These algorithms are described in the Software and
Hardware Caching section.
Virtual Cache In addition to normal caching functions, SmartRAID V
controllers also maintain a large virtual cache used for pattern
recognition and prediction. The total amount of cache space supported
by a SmartRAID V controller is fixed. Some of this total cache space is
used when physical memory modules are installed on the controller to
be used for standard cache. The space not used for standard cache is
available for virtual caching. SmartRAID V Century controllers support
a total cache space of 128MB with up to 64MB of physical cache
(depending on the number of memory modules installed). SmartRAID V
Millennium controllers support a total cache space of 512MB with up to
256MB of physical cache. As an example, if 128MB of cache memory
were installed on a SmartRAID V Millennium controller then
(512 128)MB = 384MB of virtual cache would be available.
Disk Caching
SmartRAID V Millennium controllers can be configured with up to 256MB
of cache RAM. SmartRAID V Century controllers (equipped with an
RA4050 RAID Accelerator) can be configured with up to 64MB of cache
RAM. Adding more cache to a SmartRAID V controller can result in better
RAID performance especially for RAID 5.
Seitenansicht 173
1 2 ... 169 170 171 172 173 174 175 176 177 178 179 ... 255 256

Kommentare zu diesen Handbüchern

Keine Kommentare