RAID SOFTWARE MANAGEMENT
#http://www.mrgcorner.it/howto-linux/raid1-with-linux-and-mdadm/

# add and resync spare disk
mdadm --add /dev/mdx /dev/sdx

# auto-read-only mdadm
mdadm --readwrite /dev/mdx

This means that the minimum guaranteed speed of the rebuild of the array is approx 200MB/s
cat /proc/sys/dev/raid/speed_limit_max
200000

This means that the minimum guaranteed speed of the rebuild of the array is approx 1MB/s
cat /proc/sys/dev/raid/speed_limit_min
1000

echo 50000 > /proc/sys/dev/raid/speed_limit_min

or fix setting in /etc/sysctl.conf
dev.raid.speed_limit_min=value
dev.raid.speed_limit_max=value


cat /proc/mdstat
watch -n1 cat /proc/mdstat

grub-install /dev/sdx

# pause resync
echo "idle" > /sys/block/md0/md/sync_action
echo 0 > /proc/sys/dev/raid/speed_limit_max

#http://guide.debianizzati.org/index.php/Software_Raid_1:_configurazione_e_verifiche#Avaria_di_uno_dei_due_dischi_in_raid.
#simulazione avaria disco
#  mdadm --set-faulty /dev/md0 /dev/hda1     ( --> "/" )
#  mdadm --remove /dev/md1 /dev/hda1
#  mdadm --set-faulty /dev/md1 /dev/hda2     ( --> "swap" )
#  mdadm --remove /dev/md1 /dev/hda1

#azzerare superblocchi raid sul disco
mdadm --zero-superblock /dev/hda1


#CLONE DISK PARTITION (mbr)
#Salvare in un file per le "emergenze" la struttura del disco raid completo di mbr
sfdisk -d /dev/hda > /root/mbr_hda.txt
#Restore dal file
sfdisk /dev/hdb < /root/mbr_hda.txt

#mandare disco fuori linea via software
mdadm --manage --set-faulty /dev/md1 /dev/sdc2

#dettagli sul raid
mdadm --detail /dev/md1


#CLONE DISK PARTITION (gpt)
#Salvare in un file per le "emergenze" la struttura del disco raid completo di mbr
sgdisk -b gpt_sda.txt /dev/sda

#Restore dal file
sgdisk -l gpt_sda.txt /dev/sdb

#replicare tabella disco a caldo (replico su sda, la tabella di sdb)
sgdisk -R /dev/sda /dev/sdb
sgdisk -G /dev/sda 
sgdisk -G -e /dev/sda 

mdadm --zero-superblock /dev/hda1

#dettagli sul raid
mdadm --detail /dev/md1