Soft Raid 1 on Ubuntu 12.04 with GPT disks#
prerequisites:
apt-get --yes install gdisk mdadm lvm2 cryptsetup
Create Partitions#
We will use one partition per device with maximum size.
create partitions:
wajig install gdisk
gdisk /dev/sdc
# create a new empty GUID partition table (GPT)
o
y
w
y
# add a new partition (type: Linux RAID)
gdisk /dev/sdc
n
<ENTER>
<ENTER>
<ENTER>
fd00
w
y
<ENTER>
check:
gdisk -l /dev/sdc
same for /dev/sdd.
find partition uuids:
ls -la /dev/disk/by-partuuid/
Setup RAID1#
setup raid1:
mdadm --create --verbose /dev/md0 --level=1 --raid-devices=2 /dev/sdc1 /dev/sdd1
y
fetch the UUID for the new raid:
mdadm --detail /dev/md0
add to config at /etc/mdadm/mdadm.conf for automatic assembly on boot (http://wiki.ubuntuusers.de/Software-RAID#mdadm-conf-aktualisieren):
ARRAY /dev/md0 metadata=1.2 name=locutus:0 UUID=25f29ab9:89f6e9e7:19f083c1:bc9b2d06
watch raid (md) logging:
watch cat /proc/mdstat
I usually wait for the whole resync to finish (8 hours, 3TB).
Encrypt RAID device#
cryptsetup --cipher aes-xts-plain64 --key-size 512 --hash sha512 --iter-time 5000 --use-random --verify-passphrase luksFormat /dev/md0
# uppercase YES
# check
cryptsetup luksDump /dev/md0
# test
cryptsetup luksOpen /dev/md0 crypt0
ls /dev/mapper/crypt0
Setup LVM#
http://www.gagme.com/greg/linux/raid-lvm.php
- physical extend size limitations do not apply to LVM2 (see manpage)
~65000 extends per LV
256MB physical extend size (12TB storage: 12000000MB / 65000 ~ 182 MB)
pvcreate /dev/mapper/crypt0
pvdisplay
vgcreate raid /dev/mapper/crypt0
vgdisplay
# full size of raid
lvcreate --name storage --extents 100%VG raid
lvdisplay
Format File System And Mount#
mkfs.ext3 -L storage /dev/raid/storage
mkdir /media/storage
mount /dev/raid/storage /media/storage
cd /media/storage/
df .
give ownership to self:
chown -R `id -u`:`id -g` /media/storage/
Extend#
Follow steps up to Encrypt RAID device which results in a new block device
/dev/mapper/crypt1.
Unmount:
umount /media/storage
LVM:
pvcreate /dev/mapper/crypt1
vgdisplay # VG Name is still "raid"
vgextend raid /dev/mapper/crypt1
lvdisplay # LV Name is /dev/raid/storage
# also check "LV Size"
# extend to 100% of volume group size
lvextend -l 100%VG /dev/raid/storage
lvdisplay # check "LV Size" again
Ext3 FS:
# size information (Block count, Block size)
tune2fs -l /dev/raid/storage
# run fsck
e2fsck -f /dev/raid/storage
# check max possible size
resize2fs -P /dev/raid/storage
# DO IT!
resize2fs /dev/raid/storage
Open after Reboot#
See open_storage.sh:
./open_storage.sh
Open multiple devices with one keyfile#
Don’t want to put password multiple times. Put a keyfile into an encrypted file. Mount it before unlocking and unmount it afterwards.
First, create a file to hold encrypted data:
# tried 1M and 2M
dd if=/dev/zero of=crypt_keyfile bs=4M count=1
losetup /dev/loop0 crypt_keyfile
badblocks -s -w -t random -v /dev/loop0 # random data
# prompts for uppercase YES and password twice
cryptsetup --cipher aes-xts-plain64 --key-size 512 --hash sha512 --iter-time 5000 --use-random --verify-passphrase luksFormat /dev/loop0
Open the encrypted file, make a file system and mount it:
# this will prompt for password
cryptsetup luksOpen /dev/loop0 crypt_keyfile
mkfs.ext3 /dev/mapper/crypt_keyfile
e2fsck -f /dev/mapper/crypt_keyfile
mkdir -p /tmp/crypt_keyfile
mount /dev/mapper/crypt_keyfile /tmp/crypt_keyfile
Now create a keyfile containing some random data [1]:
keyfile_size_in_bytes=$(( $(cryptsetup luksDump /dev/md0 | grep 'MK bits' | awk '{ print $NF }') / 8 ))
echo $keyfile_size_in_bytes
dd if=/dev/zero of=/tmp/crypt_keyfile/keyfile bs=${keyfile_size_in_bytes}b count=1
badblocks -s -w -t random -v /tmp/crypt_keyfile/keyfile
head -c 500 /tmp/crypt_keyfile/keyfile
Add:
# all of them will ask for their pass phrases
cryptsetup luksAddKey /dev/md0 /tmp/crypt_keyfile/keyfile
cryptsetup luksAddKey /dev/md1 /tmp/crypt_keyfile/keyfile
Umount keyfile:
umount /tmp/crypt_keyfile
cryptsetup luksClose crypt_keyfile
losetup -d /dev/loop0
To mount keyfile again:
losetup /dev/loop0 crypt_keyfile
cryptsetup luksOpen /dev/loop0 crypt_keyfile
mount /dev/mapper/crypt_keyfile /tmp/crypt_keyfile
Updated decrypt script: decrypt.sh.
Troubleshooting#
md127 http://ubuntuforums.org/showthread.php?p=10907831#post10907831:
# check /etc/mdadm/mdadm.conf
update-initramfs -u