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MaxAttach NAS 6000 Administration Guide
Maxtor MaxAttach NAS 6000 RAID Operations and the GAM
Within the MaxAttach NAS 6000, the disk arrays are controlled by the Mylex Disk Array
Controller card mounted in the Base Unit. Administrators control the functions and
configuration of the disk arrays using the Global Array Manager (GAM) Server/Client
application.
The GAM provides several features that can provide added fault tolerant to NAS 6000
systems that are described below.
Normal Array Status
During normal operations, all drives in the array are healthy and functions. From the
perspective of the user and the O/S, all the drive members of the array represent a single
local drive or volume.
Critical Array Status
A drive array is in a "critical state" whenever one and only one of it member drives have
failed. This only applies to RAID types where a drive failure can be tolerated; typically
RAID 1, RAID 3, RAID 5, and RAID 0+1. While the array is critical, it continues to
work, but the failure of any second drive in the array will result in the loss of all array data.
Hot Swap Drives
The term "Hot Swap" refers to the common practice of either inserting or removing disk
drives in an operating bus. In the MaxAttach NAS 6000, this specifically refers to the ability
to remove defective or failing drive from the system, insert new unformatted drives, and
then have the system rebuild and repair the array while maintaining normal system
operation and user access to their data.
In practical terms, this means that drives can be removed whenever they are quiescent, or
not involved in the write operation. For best results and to eliminate the possibility of
losing data, use the GAM to make the disk off line so that the amber Disk Status LED
lights. with the disk unavailable, all read/writes are canceled and the disk can be safely
exchanged.
READ/WRITE I/O OPERATIONS: When ever the disk green LED is blinking, the disk is undergoing
some sort of I/O operation. Never remove a disk drive during an I/O operation or data loss will occur.
Chapter #11 - Appendix - Disk Array RAID Concepts
11/07/01 -- Revision 2.0.03A
WARNING
Chapter #11 - Appendix - Disk Array RAID Concepts
Maxtor MaxAttach NAS 6000 RAID Operations and the GAM
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