create raid
    parted /dev/sdb
        mkpart srv ext2 34.9GB 1035GB
        mkpart bak ext2 1035GB 3001GB
    mdadm --create /dev/md5 --level=1 --raid-devices=2 /dev/sdb5 /dev/sdc5
    mdadm --create /dev/md6 --level=1 --raid-devices=2 /dev/sdb6 /dev/sdc6
    #repeat for sdc
make raid autostart
    mdadm --examine --scan
    vim /etc/mdadm/mdadm.conf
        ARRAY /dev/md/5 metadata=1.2 UUID=187d0aa0:d170df31:9c35a68f:75b2ac95 name=vbox:5
        ARRAY /dev/md/6 metadata=1.2 UUID=e1f810c6:98e1b2e5:a606a2b0:9228850e name=vbox:6
check mdadm status
    mdadm --detail /dev/md5
add new disk to degraided array
    sfdisk -d /dev/sda > part_table ; sfdisk /dev/sdb < part_table
    mdadm --manage /dev/md1 --add /dev/sdb2

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