 |
» |
|
|
|
Before you install the HP RAID 4Si product, you should plan
how you are going to configure your disks. This section contains information about
the configuration limits for the RAID 4Si controller and some examples
of typical configurations and incorrect configurations. Also, you can
use the worksheets in Appendix A “Worksheets” to help you in your physical and logical disk planning. RAID 4Si
Configuration Limits | |
Please keep in mind the following information about configuration
limits for the RAID 4Si controller: An array is a grouping of physical disks. The maximum number of physical
disks per channel is 15. The maximum number of physical
disks per array is 8. A logical drive (also called
a LUN) can contain multiple arrays when spanning
is done. For example, LUN 0 might contain two arrays: First
array: A00-00, A00-01 Second array: A01-00, A01-01
The maximum number of arrays
in a logical drive (LUN) is 8. The maximum number of arrays
per controller is 8, regardless of how the arrays are distributed
among logical drives (LUNs). For example, the maximum is reached
if the configuration consists of 4 LUNs with 2 arrays each.
Table 2-1 “Maximum Physical Disks per Controller, by
RAID Level” below shows the
physical disk limits per RAID 4Si controller.
Table 2-1 Maximum Physical Disks per Controller, by
RAID Level | RAID Level | Maximum Physical Disks per Controller |
|---|
| RAID 0 | 8 disks, if 1 disk per array | | 16 disks, if 2 disks per array | | RAID 1 and 1+0 | 16 disks, if 2 disks per array | | RAID 0, 3, 5,
3+0, and 5+0 | 24 disks, if 3 disks per array | | 32 disks, if 4 disks per array | | 40 disks, if 5 disks per array | | 48 disks, if 6 disks per array1 | | 56 disks, if 7 disks per array1 | | 60 disks, if 8 disks per array1 | 1The
maximum number of configurable disks using SC10 disk enclosures
is 40. |
Typical
Configurations | |
Some typical HP RAID 4Si configurations are as follows: Five RAID 5 arrays with 8
disks in each array. Four RAID 1+0 arrays with
1 mirror for each SC10.
Common
Misconfigurations | |
Some of the more common HP RAID 4Si misconfigurations (that
is, configuration errors) are as follows: Connecting two channels of a single controller
to a single SC10 that has both BCCs in Full Bus mode. This is an
error because both controller channels use SCSI ID 7 and are on
the same SCSI bus, which causes a conflict. Fixing this is described
in “SCSI
Misconfiguration”. Connecting two channels of
a single controller to both ports of a single BCC. This is an error
because on each BCC, a terminator must be
placed on one of the ports.
A configuration that is not completely a misconfiguration—but
which we do not recommend—is
connecting two channels of a single controller to two SC10s that
have different disk capacities, and then configuring a logical drive
that uses disks from both channels. For example, if channel 0 is
connected to an SC10 that has 9GB disk drives, and channel 1 is connected
to an SC10 that has 18GB disk drives, we do not recommend configuring
a logical drive that uses a disk from channel 0 (a 9GB drive) and
a disk from channel 1 (an 18 GB drive). This kind of configuration means
you cannot fully use the disk capacities. So, that is why we do
not recommend it (configuring a logical drive using disks that have
different capacities). Note, however, that in the same situation,
configuring a logical drive that uses disks that are all on the same channel is not considered
a misconfiguration. Using the above example (channel 0 has 9GB drives
and channel 1 has 18GB drives), you can configure
a logical drive that contains disks from only channel 0 or only channel 1—using only
drives of the same capacity is the important thing to remember. After you have finished planning how you want to configure
your disks, go to the next section, “Checking HP RAID
4Si Installation Prerequisites”. |
Printable version
