In this article, we want to teach you How To Check the RAID configuration on Linux.
RAID (redundant array of independent disks) is a way of storing the same data in different places on multiple hard disks or solid-state drives (SSDs) to protect data in the case of a drive failure.
RAID systems can be used with a number of interfaces, including SATA, SCSI, IDE, or FC (fiber channel.) There are systems that use SATA disks internally, but that have a FireWire or SCSI interface for the host system.
There are different RAID levels, however, and not all have the goal of providing redundancy.
Linux support following RAID devices:
- RAID0 (striping)
- RAID1 (mirroring)
- RAID4
- RAID5
- RAID6
- RAID10
- MULTIPATH
- FAULTY
- CONTAINER
Check the RAID configuration on Linux
At this point, we want to show you how to use Linux commands to check the RAID configuration.
Linux Raid Status
A directory named /proc/mdstat
stores essential information about all active RAID devices.
List Raid devices in Linux
Use the cat command to see the file:
cat /proc/mdstat
Or you can use the following command:
cat /etc/mdadm.conf
The mdadm is a Linux utility used to manage and monitor software RAID devices.
Monitor Raid devices in Linux
It is used in modern Linux distributions in place of older software RAID utilities such as raidtools2 or raid tools.
The main purpose of mdadm command is to combine one or more physical disk drive components into one or more logical units.
mdadm command can be used in the below way:
mdadm [mode] <raiddevice> [options] <component-devices>
To find out whether a specific device is a RAID device or a component device, you can use the mdadm command, for example:
# mdadm --query /dev/DEVICE # mdadm --query /dev/md125 # mdadm --query /dev/md12{5,6,7}
Output /dev/md125: 1157.85GiB raid10 5 devices, 0 spares. Use mdadm --detail for more detail. /dev/md126: 4.98GiB raid10 5 devices, 0 spares. Use mdadm --detail for more detail. /dev/md127: 1281.00MiB raid10 5 devices, 0 spares. Use mdadm --detail for more detail.
You can examine a RAID device in more detail, with the following command, for example:
mdadm --examine /dev/sdd3
Output /dev/sdd3: Magic : a92b4efc Version : 1.2 Feature Map : 0x1 Array UUID : 4afdd8e1:a827d278:b1613938:cdc0a6ef Name : localhost.localdomain:root Creation Time : Sun Jun 25 19:07:43 2017 Raid Level : raid10 Raid Devices : 5 Avail Dev Size : 971276288 (463.14 GiB 497.29 GB) Array Size : 1214095360 (1157.85 GiB 1243.23 GB) Data Offset : 262144 sectors Super Offset : 8 sectors Unused Space : before=262056 sectors, after=0 sectors State : clean Device UUID : b6d9043e:fc1c8b6e:e82f970f:edf597e9 Internal Bitmap : 8 sectors from superblock Update Time : Sat Dec 15 00:44:25 2018 Bad Block Log : 512 entries available at offset 72 sectors Checksum : 7c314cad - correct Events : 21001 Layout : near=2 Chunk Size : 512K Device Role : Active device 4 Array State : AAAAA ('A' == active, '.' == missing, 'R' == replacing)
Conclusion
At this point, you learn to Check the RAID configuration on Linux.
Hope you enjoy it.
May you will be interested in these articles: