Can you disable automatic mdadm startup?

Question

I am creating a RAID 10 array over four iSCSI targets. I want to control everything manually though so I can run it through heartbeat. I've unlinked the open-iscsi and mdadm scripts from /etc/rc#.d/ but the raid array is still recreated on boot up. Once the server boots up I have to do a mdadm --stop /dev/md0 and then /etc/init.d/mdadm stop to make sure it doesn't fire it up again. I commented out my array from /etc/mdadm/mdadm.conf but it just created a new one later. How can I put mdadm into a manual process so it only attempts to start or rebuild the array when I tell it to?

Solution 1

/etc/mdadm/mdadm.conf

   # by default, scan all partitions (/proc/partitions) for MD superblocks.
   # alternatively, specify devices to scan, using wildcards if desired.
  DEVICE partitions

what about scan something like /dev/null ? I mean some devices without superblocks. So mdadm cant find arrays.

Solution 2

The only solution that worked for me was (see man mdadm.conf):

# /etc/mdadm/mdadm.conf
ARRAY <ignore> UUID=xxxxxxxx:xxxxxxxx:xxxxxxxx:xxxxxxxx

Solution 3

From a RHEL 6.7 setup adding AUTO -all in /etc/mdadm.conf to disable all auto-assembly, except for ARRAYs/DEVICEs otherwise specified, seems to do the trick.

Solution 4

You don't mention what flavour of Linux you are using (I'm assuming Linux?). You can control startup behaviour on debian/ubuntu with

dpkg-reconfigure mdadm

View more solutions

Comments

[J.R.]

Ubuntu 11.04. I tried that and the only startup it asks about is the monitor which I had already turned off.

[Slawomir]

DEVICE /dev/null does not work - for anyone who reads this later, don't bother, mdadm will still auto-assemble