ICP RS Series, Руководство пользователя, Страница: 64 / 193

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Move the selection bar with the cursor keys from on entry to another (pressing the SPACE
bar again undoes your choice).
The Choose Type menu offers four different Host Drive Types. For this
example we select RAID 1 and press ENTER. ICPCON displays a
warning that all data will be destroyed after confirmation.
ICPCON allows you to limit the hard disk size for this Host Drive. This
becomes interesting when you configure disk arrays and you want to
make sure that future drives you want to bring into the disk array for
replacement purposes) fit. It would
be bad luck if the new drive only had
17508 MB. ICPCON couldn't accept
it. To avoid this occurring, you could limit the capacity of each drive to 17000 MB. Any new
18 GB drive must have at least this capacity. The 509 MB in our example would be lost. For
this example we use the full capacity and press ENTER.
The new Host Drive is created. It’s status is still build, since the ICP Controller synchronizes
both drives.
Upon successful completion of this process the status of this RAID 1 Disk Array changes
into ready, i.e., the data is fully redundant.
The functioning of a RAID-1, or mirroring, disk array, is easy to understand: On the ICP Con-
troller, one write-access from the host computer is transformed into two write-accesses (to
both Logical Drives forming the mirroring array). If the two Logical Drives are built of hard
disks, which are connected with different SCSI channels of the ICP Controller, both write-
accesses are performed simultaneously (this method is often called
Disk Duplexing ). During
a read-access of the host computer the data will be read from the Logical Drive whose hard
disk has the fastest access to the data requested.
If a hard disk should fail (for instance due to a mechanical defect), all data is still available
on the other Logical Drive. In this event, the controller gives an acoustical alarm.
C.5 Example 3 - Installing a RAID 5 Disk Array
This example is applicable to ICP Controllers with the RAIDYNE® firmware.
Press the <CTRL><G> key combination when the ICP BIOS message comes up (shortly af-
ter switching on the computer) and load ICPCON from the Flash-RAM of the ICP Controller.
In this case no operating system is required.