currently I'm fighting since 4 weeks with a retarded server, well whenever I got some time besides

• fixing bugs
• keeping the system running, because the main server is offline since 2 month now
• helping people with problems
• fighting with power outages
• fixing servers
• and actually coding doing research in the left over time

anyway for some reasons the raid system keeps failing all the time, specially it keeps forgetting it's devices.

So just some small things for me to remember for the next time...

• removing existing raid stuff: mdadm --zero-superblock /dev/sd[c,d,e,f,g,h,i,j,k,l,m,n,o,p]1
• stopping a raid: mdadm --stop /dev/md_d3
• getting some info's about the raid: mdadm --examine /dev/sd[c-p]1
• trying to assemble a raid: mdadm -v -A /dev/md_d3 /dev/sd[c,d,e,f,g,h,i,j,k,l,m,n,o,p]1
• creating a large raid0 for testing: mdadm --create --verbose --force /dev/md3 --level=raid0 --raid-devices=14 /dev/sd{c,d,e,f,g,h,i,j,k,l,m,n,o,p}1
• creating a raid6: mdadm --create --verbose --force --name=data /dev/md3 --level=raid6 --raid-devices=12 --spare-devices=2 /dev/sd{c,d,e,f,g,h,i,j,k,l,m,n,o,p}1
• storing the generated configuration: mdadm --examine --scan --config=mdadm.conf >> /etc/mdadm/mdadm.conf

solution: found here

now just wait a tiny bit for the rebuild...

md3 : active raid6 sdp1[13](S) sdo1[12](S) sdn1[11] sdm1[10] sdl1[9] sdk1[8] sdj1[7] sdi1[6] sdh1[5] sdg1[4] sdf1[3] sde1[2] sdd1[1] sdc1[0]

9765510400 blocks level 6, 64k chunk, algorithm 2 [12/12] [UUUUUUUUUUUU]

[>....................] resync = 0.7% (7591112/976551040) finish=1074.7min speed=15024K/sec