Advantech DNS-3200 user manual RAID Minimum Disk Requirements, Understanding Array and Disk States

Chapter 4 Managing Arrays and Disks

4.1 RAID Minimum Disk Requirements

The following table lists the minimum and maximum number of disks for each RAID level.

Table 4.1: Min and Max Disks for RAID levels

RAID Level	Minimum Number of	Maximum Number of
	Disks	Disks
Volume	1	32
RAID0	2	32
RAID1	2	2
RAID1n	3	16
RAID10	4	32
RAID10n	6	32
RAID5	3	16
RAID50	6	32

4.2 Understanding Array and Disk States

The controller uses states to report the status of arrays and disks. To ensure the health of your data, it is important to understand what each array and disk state means as well as what causes them to change.

Array States

Within the management applications, an array is a logical device that can exist in one of three states: NORMAL, CRITICAL, or OFFLINE. In RAIDConsole, these states are shown in the Array List area in a column named State. Within the bcadm program, these states also shown in the column named State. The states are defined as follows:

Whether an array is marked as CRITICAL or OFFLINE depends on the type of array and how many disks within the array have failed. Note the following changes in state:

DNS-3200 User’s Manual 40