Day To Day Management Of Raid Arrays - Red Hat ENTERPRISE LINUX 3 - INTRODUCTION TO SYSTEM ADMINISTRATION Administration Manual

Chapter 5. Managing Storage
Some of the more notable sections in this entry are:
— Shows the device file name for the RAID array
• raiddev
— Defines the RAID level to be used by this RAID array
•
raid-level
• nr-raid-disks
• nr-spare-disks
or more spare disk partitions; these partitions can automatically take the place of a malfunctioning
disk
,
• device raid-disk
array
Next, it is necessary to actually create the RAID array. This is done with the
our example
/etc/raidtab
command:
mkraid /dev/md0
The RAID array
/dev/md0
different than for formatting and mounting a single disk drive.

5.9.9. Day to Day Management of RAID Arrays

There is little that needs to be done to keep a RAID array operating. As long as no hardware problems
crop up, the array should function just as if it were a single physical disk drive. However, just as a
system administrator should periodically check the status of all disk drives on the system, the RAID
arrays' status should be checked as well.
5.9.9.1. Checking Array Status With
The file
/proc/mdstat
system. Here is a sample
Personalities : [raid1]
read_ahead 1024 sectors
md1 : active raid1 hda3[0] hdc3[1]
522048 blocks [2/2] [UU]
md0 : active raid1 hda2[0] hdc2[1]
4192896 blocks [2/2] [UU]
md2 : active raid1 hda1[0] hdc1[1]
128384 blocks [2/2] [UU]
unused devices:
On this system, there are three RAID arrays (all RAID 1). Each RAID array has its own section in
and contains the following information:
/proc/mdstat
The RAID array device name (not including the
•
The status of the RAID array
•
12. Note that since the RAID array is composed of partitioned disk space, the device file name of a RAID array
does not reflect any partition-level information.
— Indicates how many physical disk partitions are to be part of this array
— Software RAID under Red Hat Enterprise Linux allows the definition of one
— Together, they define the physical disk partitions that make up the RAID
file, we would create the
is now ready to be formatted and mounted. The process at this point is no
is the easiest way to check on the status of all RAID arrays on a particular
(view with the command
mdstat
!
none
12
/dev/md0
/proc/mdstat
cat /proc/mdstat
part)
/dev/
program. Using
mkraid
RAID array with the following
):
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