Okay, this is starting to get pretty frustrating. I've read most of the other answers on this site that have anything to do with this issue but I'm still not getting anywhere. I have a RAID 6 array with 10 devices and 1 spare. The OS is on a completely separate device. At boot only three of the 10 devices in the raid are available, the others become available later in the boot process. Currently, unless I go through initramfs I can't get the system to boot - it just hangs with a blank screen. When I do boot through recovery (initramfs), I get a message asking if I want to assemble the degraded array. If I say no and then exit initramfs the system boots fine and my array is mounted exactly where I intend it to. Here are the pertinent files as near as I can tell. Ask me if you want to see anything else.

# mdadm.conf
#
# Please refer to mdadm.conf(5) for information about this file.
#

# by default (built-in), scan all partitions (/proc/partitions) and all
# containers for MD superblocks. alternatively, specify devices to scan, using
# wildcards if desired.

#DEVICE partitions containers

# auto-create devices with Debian standard permissions
# CREATE owner=root group=disk mode=0660 auto=yes

# automatically tag new arrays as belonging to the local system
HOMEHOST <system>

# instruct the monitoring daemon where to send mail alerts
MAILADDR root

# definitions of existing MD arrays

# This file was auto-generated on Tue, 13 Nov 2012 13:50:41 -0700
# by mkconf $Id$
ARRAY /dev/md0 level=raid6 num-devices=10 metadata=1.2 spares=1 name=Craggenmore:data UUID=37eea980:24df7b7a:f11a1226:afaf53ae

Here is fstab

# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).

#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
# / was on /dev/sdc2 during installation
UUID=3fa1e73f-3d83-4afe-9415-6285d432c133 /               ext4    errors=remount-ro 0       1
# swap was on /dev/sdc3 during installation
UUID=c4988662-67f3-4069-a16e-db740e054727 none            swap    sw              0       0
# mount large raid device on /data
/dev/md0    /data   ext4    defaults,nofail,noatime,nobootwait  0   0

output of cat /proc/mdstat

Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md0 : active raid6 sda[0] sdd[10](S) sdl[9] sdk[8] sdj[7] sdi[6] sdh[5] sdg[4] sdf[3] sde[2] sdb[1]
      23441080320 blocks super 1.2 level 6, 512k chunk, algorithm 2 [10/10] [UUUUUUUUUU]

unused devices: <none>

Here is the output of mdadm --detail --scan --verbose

ARRAY /dev/md0 level=raid6 num-devices=10 metadata=1.2 spares=1 name=Craggenmore:data UUID=37eea980:24df7b7a:f11a1226:afaf53ae
   devices=/dev/sda,/dev/sdb,/dev/sde,/dev/sdf,/dev/sdg,/dev/sdh,/dev/sdi,/dev/sdj,/dev/sdk,/dev/sdl,/dev/sdd

Please let me know if there is anything else you think might be useful in troubleshooting this... I just can't seem to figure out how to change the boot process so that mdadm waits until the drives are ready to build the array. Everything works just fine if the drives are given enough time to come online.

edit: changed title to properly reflect situation