HP D7171A - NetServer - LPr Manual page 8
Netserver accessories
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Also See for D7171A - NetServer - LPr:
- Installation manual (182 pages) ,
- User manual (126 pages) ,
- Upgrade manual (97 pages)
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Hard Disk Drives
SCSI hard disk drives are available in a variety of capacities from 4 to 18 GB, with higher
capacity drives (36 GB) planned for mid-1999. HP offers drives at two rotational speeds:
7200 and 10,000 rpm. The higher speed drive offers shorter seek times and improved
system performance.
Drives are available for either internal or external storage systems. HP offers two versions
of external storage: rack-optimized or pedestal/standalone configurations.
HP's position as a leading server vendor gives the company considerable leverage with
leading drive vendors. HP has close relationships with these drive vendors, allowing HP to
work with them on new drive technologies and standards, to thoroughly test these
technologies with HP NetServer hardware and software, and to bring them to market in
cost-effective and timely ways. As an example, HP offers proactive warranty replacement
on drives, meaning that the company will replace them for you if HP server management
software indicates a problem—even if a failure has not yet occurred. Current areas of
cooperation with drive vendors include both higher capacity and faster drives, enhanced
drive connection mechanisms, and better availability and management features.
Performance improvements include 10K RPM drives and low voltage differential (Ultra2)
SCSI technology.
HP NetServers offers standard SCSI controllers in all server systems. Additional SCSI,
Disk Array, or Fibre Channel controllers may be added. The HP NetServer website
provides lists of tested controller cards, organized by platform, as well as more information
about each of the controller products.
HP NetServer RAID Configurations
RAID can be implemented in software or hardware. Software-based RAID uses host CPU
cycles and system memory adding processing overhead that may impact system
performance. Disk array controllers (DAC), the hardware solution, transfer the overhead
from the host CPU to specialized hardware that typically performs better than the software
bad drive is
replaced
Figure 4. Hot Swap versus Hot Spare
three academics from the University of California at Berkeley as a way to organize and
protect stored data. Additional levels have since been developed to enhance performance
and data redundancy. Hewlett-Packard NetRAID family controllers offer a choice of seven
X
array controller
Hot Swap
rebuilds data
RAID.
The DAC can be programmed to support a
hot spare drive configuration. With this
arrangement, if a drive should fail, the
system can automatically begin rebuilding
Hot Spare
to the hot spare drive. See Figure 4 for an
explanation of the differences between a
hot swap and a hot spare configuration.
There are several RAID levels to choose
from whether the implementation be
with software or hardware. Five levels
(1 through 5) were defined when the RAID
concept was first proposed in 1988 by
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