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--- nas:build_a_linux_nas:create_a_software_raid_array [2021/09/25 16:11] – peter
+++ nas:build_a_linux_nas:create_a_software_raid_array [2021/09/26 12:00] (current) – [Ensure the RAID Array is reassembled automatically each time the system boots] peter
@@ Line 1: / Line 1: @@
 ====== NAS - Build a Linux NAS - Create a Software RAID Array ======
+===== Check the disk partitions to be used in the RAID =====
+<code bash>
+mdadm --examine /dev/sd[b-d]1
+or
+mdadm --examine /dev/sdb1 /dev/sdc1 /dev/sdd1
+</code>
+returns:
+<code bash>
+mdadm: No md superblock detected on /dev/sdb1
+mdadm: No md superblock detected on /dev/sdc1
+mdadm: No md superblock detected on /dev/sdd1
+</code>
+<WRAP info>
+**NOTE:**  There is no any defined RAID on the sdb1, sdc1 and sdd1 drives so far, which is why no superblocks are detected.
+</WRAP>
+----
 ===== Create a Software RAID Array =====
@@ Line 8: / Line 32: @@
 or
-sudo mdadm --create --verbose /dev/md0 --level=5 --raid-devices=3 --spare-devices=1 /dev/sd{b,c,d, e}1
+sudo mdadm --create --verbose /dev/md0 --level=5 --raid-devices=3 --spare-devices=1 /dev/sd{b,c,d,e}1
 </code>
@@ Line 16: / Line 40: @@
   * This device represents the RAID 5 of /dev/sdb1, /dev/sdc1 and /dev/sdd1.
   * Obviously other RAID types could be used instead.
+If the following message is seen: **Device or resource busy**, then reboot the OS.
 </WRAP>
@@ Line 24: / Line 50: @@
 <code bash>
 sudo mdadm --detail --scan | sudo tee -a /etc/mdadm/mdadm.conf
+or
+sudo mdadm --detail --scan --verbose | sudo tee -a /etc/mdadm/mdadm.conf
 </code>
+returns:
+<code bash>
+ARRAY /dev/md/0 level=raid5 num-devices=3 metadata=1.2 spares=1 name=xenial:0 UUID=c7a2743d:f1e0d872:b2ad29cd:e2bee48c
+      devices=/dev/sdb1,/dev/sdc1,/dev/sdd1
+</code>
 <WRAP info>
@@ Line 36: / Line 72: @@
 ----
-===== Check the RAID Status =====
+===== Check the RAID Details =====
 <code bash>
@@ Line 50: / Line 86: @@
 **NOTE:**  This also displays not only the health, but also the sync status.
 </WRAP>
+----
+===== Check Raid Status =====
+<code bash>
+cat /proc/mdstat
+</code>
+returns:
+<code bash>
+Personalities : [raid6] [raid5] [raid4]
+md0 : active raid5 sdc1[4] sdd1[3](S) sdb1[1] sda1[0]
+      1953520640 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/2] [UU_]
+      [>....................]  recovery =  4.3% (42161792/976760320) finish=215.1min speed=72409K/sec
+</code>