Differences

This shows you the differences between two versions of the page.

--- raid:mdadm:check_the_raid_status [2021/09/13 22:59] – created peter
+++ raid:mdadm:check_the_raid_status [2021/09/14 08:41] (current) – peter
@@ Line 1: / Line 1: @@
 ====== RAID - mdadm - Check the RAID status ======
+<code bash>
+cat /proc/mdstat
+</code>
+returns:
+<code bash>
+Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] [multipath]
+md0 : active raid6 sdf3[0] sdd3[7] sdg3[6] sdh3[5] sdc3[4] sdb3[2] sda3[3] sde3[1]
+      46824429696 blocks super 1.0 level 6, 64k chunk, algorithm 2 [8/8] [UUUUUUUU]
+      bitmap: 21/59 pages [84KB], 65536KB chunk
+</code>
+<WRAP info>
+**NOTE:**
+  * **Personalities**:  What RAID levels the kernel currently supports.
+    * This can be changed by either changing the raid modules or recompiling the kernel.
+    * Possible personalities include: [raid0] [raid1] [raid4] [raid5] [raid6] [linear] [multipath] [faulty]
+      * **[faulty]** is a diagnostic personality; it does not mean there is a problem with the array.
+  * **md0**:  The device is /dev/md0.
+  * **active**:  The RAID is active and started.
+    * An inactive array is usually faulty. Stopped arrays are not visible here.
+  * **raid6**:  The type of RAID array and the component devices are:
+    * **sdf3[0]** is device 0.
+    * **sdd3[7]** is device 7.
+    * **sdg3[6]** is device 6.
+    * **sdh3[5]** is device 5.
+    * **sdc3[4]** is device 4.
+    * **sdb3[2]** is device 2.
+    * **sda3[3]** is device 3.
+    * **sde3[1]** is device 1.
+      * The order in which the devices appear in this line means nothing.
+  * **46824429696 blocks**:  The usable size of the array in blocks.
+  * **super 1.0**:  The array uses a 1.0 [[https://raid.wiki.kernel.org/index.php/RAID_superblock_formats|superblock]].
+  * **level 6**:  Confirms this is a level 6 array.
+  * **64k chunk**:  Has a chunk size of 64k.
+    * This is the size for 'chunks' and is only relevant to raid levels that involve striping (1,4,5,6,10).
+    * The address space of the array is conceptually divided into chunks and consecutive chunks are striped onto neighboring devices.
+  * **algorithm 2**:  Uses algorithm 2.
+  * **[8/8]**:  The first number is the number of a complete raid devices as defined.  The second number is how many devices are in use.
+  * **[UUUUUUUU]**:  The status of each device.
+    * **F**:  The drive has failed.
+    * **U**:  The drive is used and working fine.
+    * **_**:  The drive is down.
+</WRAP>
+----
+<code bash>
+mdadm --detail /dev/md1
+</code>
+returns:
+<code bash>
+/dev/md1:
+        Version : 1.0
+  Creation Time : Tue Mar  6 17:46:54 2018
+     Raid Level : raid6
+     Array Size : 46824429696 (44655.26 GiB 47948.22 GB)
+  Used Dev Size : 7804071616 (7442.54 GiB 7991.37 GB)
+   Raid Devices : 8
+  Total Devices : 8
+    Persistence : Superblock is persistent
+  Intent Bitmap : Internal
+    Update Time : Tue Sep 14 00:02:02 2021
+          State : active
+ Active Devices : 8
+Working Devices : 8
+ Failed Devices : 0
+  Spare Devices : 0
+         Layout : left-symmetric
+     Chunk Size : 64K
+           Name : 1
+           UUID : 85d45e53:913fde8a:55ba7e06:ee932838
+         Events : 16304341
+    Number   Major   Minor   RaidDevice State
+       8       83        0      active sync   /dev/sdf3
+       8       67        1      active sync   /dev/sde3
+       8        3        2      active sync   /dev/sda3
+       8       19        3      active sync   /dev/sdb3
+       8       35        4      active sync   /dev/sdc3
+       8      115        5      active sync   /dev/sdh3
+       8       99        6      active sync   /dev/sdg3
+       8       51        7      active sync   /dev/sdd3
+</code>
+----