Menu Advanced Setup: Configure Host Drives - ICP RS Series User Manual

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The Array Drive has entered the build state, i.e., the parity information is currently gener-
ated. After completion of the build process, the Array Drive's state is ready, i.e., fault toler-
ant.
Notes on the Configuration of RAID 0, 1, 4, 5 and 10 Arrays Drives
(1) Use preferably Logical Drives of the type disk to build an Array Drive.
Of course, RAID Array Drives can be configured with Logical Drives of the type chain, too,
but the aspects of security should be taken into consideration as well. For regular RAID Ar-
ray Drives, type disk Logical Drives are used.
(2) The Logical Drives of an Array Drive should have the same storage capacity.
In order not to waste valuable storage capacity, you should only use Logical Drives that
have the same storage capacity for an Array Drive.
(3) The Hot Fix drive provides the utmost security.
One of the reasons for which RAID Array Drives are used definitely lies with the redundancy
they provide, that is, the data security you still have even in the event of a hard disk failure,
thus resting assured against loss of data and time. For the purpose of the following consid-
erations, we define the term time without redundancy, TWR. Set apart the time needed to
set up the Array Drive (state build), the time without redundancy should be kept as short as
possible. Let us assume that one of the hard disks of a RAID 5 Array Drive fails. The Array
Drive is without redundancy. TWR starts to run. Any superfluous prolongation of the TWR
(because you have to get a replacement hard disk, or because you did not realize the failure
immediately since you didn't hear the ICP Controller's alarm signal, or because nobody
checked the file server) increases the risk of data loss which will occur if a second hard disk
should fail. Therefore, new redundancy should be created as soon as possible and in an
entirely automated manner. Integrating a Hot Fix drive as an immediately available and
auto-replacing hard disk is the only way to keep the TWR as short as possible. Only a Hot
Fix drive can ensure optimal Array Drive security and constant data availability. Of course a
Hot Fix drive is not mandatory. If you control the Array Drive at regular intervals and imme-
diately replace a defective hard disk (by shutting down the system or Hot Plug), you can do
without a Hot Fix drive.
J.4.7 Menu Advanced Setup: Configure Host Drives
This main menu option allows you to configure Host Drives (level of hierarchy 4). As al-
ready mentioned before, these are the drives the Host Computer is aware of. Host Drives
can consist of a single hard disk, or of many hard disk com-
bined to a RAID 5 Array Drive. The menus Split/Merge Host
Drives and Partition Host Drives are only available if ICPCON
was loaded with <CTRL><G> from the ICP Controller's Flash-
RAM. The additional capacity resulting from an Online Ca-
pacity Expansion is shown as another Host Drive. If you ex-
panded the capacity of the Array Drive a second time, there
would be three Host Drives, belonging to one and the same
Array Drive. Since there is currently no operating system,
which supports "growing hard disks", this expansion method
is the only safe way to introduce new capacity.