Create a RAID 1 volume from two drives.

mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sdc /dev/sde

To add RAID device 'md0' to /etc/mdadm.conf so that it is recognized the next time you boot.

mdadm -Es | grep '''md0'''  >>/etc/mdadm.conf

View the status of a multi disk array.

mdadm --detail /dev/md0

View the status of all multi disk arrays.

cat /proc/mdstat

Note: add raid1 to /etc/initramfs-tools/modules and rebuild initrd

Situation: Raid 5, with 6 disks

Final: Raid 5, with 8 disks

  # mdadm --add /dev/md127 /dev/sdh1 
  mdadm: added /dev/sdh1
  # mdadm --add /dev/md127 /dev/sdj1 
  mdadm: added /dev/sdj1
  # mdadm --grow --raid-devices=8 /dev/md127 
  mdadm: Need to backup 1344K of critical section..
  mdadm: ... critical section passed.
  #

• Migrating To RAID1 Mirror on Sarge
• Debian RAID

# mdadm --detail /dev/md0
/dev/md0:
        Version : 1.2
  Creation Time : Sat Feb  2 06:51:55 2013
     Raid Level : raid6
     Array Size : 11717889024 (11175.05 GiB 11999.12 GB)
  Used Dev Size : 1952981504 (1862.51 GiB 1999.85 GB)
   Raid Devices : 8
  Total Devices : 8
    Persistence : Superblock is persistent

    Update Time : Mon Jul 15 20:30:57 2013
          State : active, degraded 
 Active Devices : 7
Working Devices : 8
 Failed Devices : 0
  Spare Devices : 1

         Layout : left-symmetric
     Chunk Size : 512K

           Name : tukan2:0  (local to host tukan2)
           UUID : bf36da8d:5009d151:4f3ee49d:92059128
         Events : 1535927

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       33        1      active sync   /dev/sdc1
       2       8       49        2      active sync   /dev/sdd1
       3       8       65        3      active sync   /dev/sde1
       4       8       97        4      active sync   /dev/sdg1
       5       0        0        5      removed
       6       8      129        6      active sync   /dev/sdi1
       7       8      145        7      active sync   /dev/sdj1

       8       8      113        -      spare   /dev/sdh1

 # cat /sys/block/md0/md/sync_action 
 frozen

 echo repair >/sys/block/md0/md/sync_action

Result:

# mdadm --detail /dev/md0
/dev/md0:
        Version : 1.2
  Creation Time : Sat Feb  2 06:51:55 2013
     Raid Level : raid6
     Array Size : 11717889024 (11175.05 GiB 11999.12 GB)
  Used Dev Size : 1952981504 (1862.51 GiB 1999.85 GB)
   Raid Devices : 8
  Total Devices : 8
    Persistence : Superblock is persistent

    Update Time : Mon Jul 15 20:38:59 2013
          State : active, degraded, recovering 
 Active Devices : 7
Working Devices : 8
 Failed Devices : 0
  Spare Devices : 1

         Layout : left-symmetric
     Chunk Size : 512K

 Rebuild Status : 0% complete

           Name : tukan2:0  (local to host tukan2)
           UUID : bf36da8d:5009d151:4f3ee49d:92059128
         Events : 1536481

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       33        1      active sync   /dev/sdc1
       2       8       49        2      active sync   /dev/sdd1
       3       8       65        3      active sync   /dev/sde1
       4       8       97        4      active sync   /dev/sdg1
       8       8      113        5      spare rebuilding   /dev/sdh1
       6       8      129        6      active sync   /dev/sdi1
       7       8      145        7      active sync   /dev/sdj1

• http://www.3ware.com/support/download.asp (the 900kB one!)
• http://lena.franken.de/linux/3ware/

  /c0 add type=SINGLE disk=0

smartctl -d 3ware,1 -a /dev/twa0
smartctl -d 3ware,8 -a /dev/twa0 -T permissive

ibm_utl_aacraid_9.10_linux_32-64.zip

HP DL360 G6 P410i * http://h20000.www2.hp.com/bizsupport/TechSupport/SoftwareIndex.jsp?lang=en&cc=us&prodNameId=3902575&prodTypeId=329290&prodSeriesId=3902574&swLang=8&taskId=135&swEnvOID=4004

At Debian you need to

 apt-get install ia32-libs

and hpacucli-8.75-12.0.noarch.rpm. Example:

  controller all show config
  ctrl slot=0 create type=ld drives=1I:1:3 raid=0