Install at first the raid tools:
emerge -av sys-fs/mdadm
Load the raid module:
modprobe raid5
Create partitions on the three hard-disks with fdisk and type fd.
fdisk /dev/sdb fdisk /dev/sdc fdisk /dev/sdd
Create md devices:
cd /dev && MAKEDEV md
New create the raid with:
mdadm --create /dev/md0 --level 5 --raid-devices 3 /dev/sd[[bcd]]1
To see progress on build:
watch -n 1 cat /proc/mdstat
Store raid in config file:
mdadm --detail --scan >> /etc/mdadm.conf
To see more details for raid:
mdadm --detail /dev/md0
Edit the file /etc/mdadm.conf and add there:
MAILADDR idefix@server.idefix.lan
Test email delivery:
mdadm -Ft --scan
You can see in /proc/mdstat which device failed:
md0 : active raid5 sdb1[3] sdd1[2] sdc1[1] 2930271872 blocks level 5, 64k chunk, algorithm 2 [3/2] [_UU]
Remove it with:
mdadm -r /dev/md0 /dev/sdb1
Create a partition on the new disk with type 0xFD and add it to the raid with:
mdadm -a /dev/md0 /dev/sdb1
You can see now in /proc/mdstat that the raid is recovering the data:
cat /proc/mdstat Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] [multipath] [faulty] md0 : active raid5 sdb1[3] sdd1[2] sdc1[1] 2930271872 blocks level 5, 64k chunk, algorithm 2 [3/2] [_UU] [>....................] recovery = 0.8% (12625280/1465135936) finish=302.8min speed=79923K/sec unused devices: <none>
emerge -av lvm2 rc-update add device-mapper boot rc-update add lvm boot
Scan for devices:
vgscan mdadm -Ac partitions -m 0 /dev/md0
At first we create our backup storage. For this create partition on the disks and select as type raid autodetect. Now we create the raid with:
mdadm --create /dev/md0 --level=stripe --raid-devices=2 /dev/sde1 /dev/sdf1
Now we create the lvm2:
vgscan vgchange -a y pvcreate /dev/md0 vgcreate vg /dev/md0 lvcreate -L20G -nyavdr vg lvcreate -L3T -nbackup-video0 vg mkfs.ext4 /dev/vg/backup-video0
Now we mount the disks:
mount /dev/vg/backup-video0 /mnt/backup-video0 mount video:/video0 /video0
Now we copy the data:
cd /video0 rsync -av --delete . /mnt/backup-video0/
Replace the first disk with a new one like it is descriped in case of a disk failure. Wait till the raid is restored. Repeat that step for every disk in your raid.
Now we have to resize the raid:
mdadm -G /dev/md0 -z max
You have to wait till the resize is complete, check with:
cat /proc/mdstat
Now we resize the lvm:
pvresize /dev/md0
Now we resize the logical volume:
lvresize -l +100%FREE /dev/vg/video0
Now we resize the filesystem, I use ext4 so do:
resize2fs /dev/vg/video0