On 02/10/2014 07:13 PM, Justin Stephenson wrote:

Hello Phil,

You are 100% correct. Thanks for your email. I had 2 separate ARRAY
entries in my mdadm.config file. When I added the spare, I added the new
information to the config file but did not remove the old entry. Total
newbie mistake.

- I commented out all the previous entries in the mdadm.config file (it
had a devices lists instead of the UUID information)

- I successfully assembled the array (mdadm --assemble /dev/md0 
/dev/sdb1 etc...)

- I  updated the config file using the information from mdadm -Esc
partitions | grep UUID and deleted the old entries.

- I uncommented the fstab entry for the array and rebooted.


Everything is working perfectly now.


I remember reading somewhere that mdadm can run without the config file
by using the RAID uuid and the information in the superblocks. Would
this be more reliable?

Thanks Again

You're welcome.

I suggest you trim the mdadm.conf file even further--I only specify name
and uuid, so device changes don't interfere with assembly.  Like so
(slightly edited):

MAILFROM mdadm@example.com
MAILADDR philip@example.com

DEVICE /dev/sd[a-z][1-9]

# Mirrored Boot partitions
ARRAY /dev/md1 UUID=75c011c6:caeb06ea:ec7e3370:aa4f3320

# Far mirror (Raid10) core operations
ARRAY /dev/md2 UUID=6b4858da:f24e2567:34e73fe5:b8f2c118

# Bulk redundant (Raid6) storage
ARRAY /dev/md3 UUID=04f3706c:79a3cd73:8a558eee:93ec1879


HTH,

Phil

ps. Don't forget to update your initramfs after any changes to mdadm.conf!