====== Software Raid (MD) ======

Find more information how to setup the raid in [[deb720:mdadm|Debian 7.2: Software RAID (MD)]]

===== Trouble shooting Raid Arrays =====

Raid Array is not built during boot, because of duplicate array definitions in mdadm.conf. Replace (or comment out) the block of three lines following # definitions of existing MD arrays so that each array is declared by your most recent scan.

A typical scenario for RAID arrays that fail to build on boot is that either they have not been updated in the initramfs or they are not set to run at boot time. A really quick scan through the guide you referenced doesn't appear to mention these steps, but I could be wrong. On Debian systems the commands are:

  dpkg-reconfigure mdadm # Choose "all" disks to start at boot
  update-initramfs -u # Updates the existing initramfs, is called automatically by dpkg-reconfigure

  # mdadm --assemble --scan
  # mdadm --readwrite /dev/md0

==== Resources ====

  * [[https://www.howtoforge.com/software-raid1-grub-boot-debian-etch|How To Set Up Software RAID1 On A Running System]]
  * [[http://unix.stackexchange.com/questions/53542/how-to-determine-the-filesystem-of-an-unmounted-device|How to determine the filesystem of an unmounted device]]
  * [[https://linuxexpresso.wordpress.com/2010/03/31/repair-a-broken-ext4-superblock-in-ubuntu/|Repair a broken Ext4 Superblock]]
  * [[https://www.thomas-krenn.com/en/wiki/Mdadm_recovery_and_resync|Mdadm recovery and resync]]
  * [[http://unix.stackexchange.com/questions/78804/how-to-mount-a-disk-from-destroyed-raid-system|How to mount a disk from destroyed raid system]]
  * [[http://unix.stackexchange.com/questions/199101/debian-mounting-a-raid-array|Debian : Mounting a raid array]]
  * [[http://unix.stackexchange.com/questions/64889/how-to-mount-recover-data-on-a-disk-that-was-part-of-a-mdadm-raid-1-on-another-m|How to mount/recover data on a disk that was part of a mdadm raid 1 on another machine]]
  * [[https://wiki.debian.org/FileSystem|Debian FileSystems]]