Mylex AcceleRAID 170, Installation Manual

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G-20 AcceleRAID 170 Installation Guide
To use the standby rebuild feature, you should always maintain a standby
SCSI disk in your system. When a disk fails, the standby disk will
automatically replace the failed drive and the data will be rebuilt. The system
administrator can disconnect and remove the bad disk and replace it with a
new disk. The administrator can then make this new disk a standby.
The standby replacement table has a limit of 8 automatic replacements in any
session (from power-on/reset to the next power-off/reset). When the limit of
8 is reached and a disk failure occurs, the standby replacement will occur but
will not be recorded in the replacement table.
To clear the “standby replacement” table, reboot the system from a DOS
bootable floppy, run the configuration utility and select the option ‘view/
update configuration’ from the main menu. A red box labeled ‘Drive Remap
List’ will be displayed. Selecting the box will allow you to continue. You
should save the configuration without making any changes, and exit the
configuration utility. This will clear the replacement table. You may now
proceed to boot your system and continue normal operations.
In normal use, the replacement table limit of 8 should not cause any
problems. Assuming that a disk fails about once a year (drives we support
generally come with a 5-year warranty), the system would run continuously
for a minimum of eight years before the table would need to be cleared.
Stripe Order
The order in which SCSI disk drives appear within a drive group. This order
must be maintained, and is critical to the controller’s ability to “rebuild”
failed drives.
Stripe Size
The size, in kilobytes (1024 bytes) of a single I/O operation. A stripe of data
(data residing in actual physical disk sectors, which are logically ordered
first to last) is divided over all disks in the drive group.
Stripe Width
The number of striped SCSI drives within a drive group.
Striping
The storing of a sequential block of incoming data across multiple SCSI
drives in a group. For example, if there are 3 SCSI drives in a group, the data
will be separated into blocks and block 1 of the data will be stored on SCSI