This tutorial is about how to create partition on data disk and merge it with OS disk to extend the size of /.
We will make the disk structure to:
/dev/vda – os disk
— /dev/vda1 – /boot
— /dev/vda2 – LVM (/ included)
/dev/vdb – data disk
— /dev/vdb1 – LVM (extend to /)
/dev/vdc – initialization file
Warning: Reinstallation will destroy the data!
Please remove the partition before reinstalling OS. (Run fdisk /dev/vdb and type d)
1. Update and install related software
Debian & Ubuntu:
apt-get update apt-get -y install kpartx lvm2
CentOS & Fedora:
yum -y install kpartx lvm2
2. Create partition
fdisk /dev/vdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x1ea1ca70.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won’t be recoverable.
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
Command (m for help): n #type n to create new partition
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p): #type p, or press Enter, to create primary partition (max 4)
Using default response p
Partition number (1-4, default 1): #press Enter
Using default value 1
First sector (2048-67108863, default 2048): #press Enter
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-67108863, default 67108863): #press Enter or use customized size
Using default value 67108863
Command (m for help): #type t, to change partition type
Selected partition 1 #it will be automatically selected if there is only 1 partition, otherwise you need to type it manually
Hex code (type L to list codes): 8e #type 8e (Linux LVM)
Changed system type of partition 1 to 8e (Linux LVM)
Command (m for help): #type w, to save. Warning: type q to quit if there is something wrong.
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
3. Create PV
pvcreate -yff /dev/vdb1
4. Extend new PV to /
Get the existed VG Name:
VGNAME=`vgdisplay | grep "VG Name" | awk '{print $3}'`
Extend / with /dev/vdb1:
vgextend $VGNAME /dev/vdb1
5. Resize /
5.1. Check free PE Size
PESIZE=`vgdisplay $VGNAME | grep "Free PE / Size" | awk '{print $5}'`
5.2. Check the location of /
df / | egrep "^/dev" | awk '{print $1}'
Please copy the output, this will be the location of /. It is /dev/mapper/debian-root in this tutorial.
5.3. Resize the LV where / located [1]
lvresize -l +$PESIZE /dev/mapper/debian-root
5.4. Resize the partition where / located
resize2fs /dev/mapper/debian-root
Please wait since it may take several minutes. [2]
6. Validation
df -h
You will see the new size of your disk. Example output:
Filesystem Size Used Avail Use% Mounted on
rootfs 54G 807M 51G 2% /
udev 10M 0 10M 0% /dev
tmpfs 101M 224K 101M 1% /run
/dev/mapper/debian-root 54G 807M 51G 2% /
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 201M 0 201M 0% /run/shm
/dev/vda1 472M 28M 420M 7% /boot
Possible errors
[1]
Path required for Logical Volume "dm-0"
Please provide a volume group name
Run `lvresize --help' for more information.
1.1. Find the real path of "dm-0":
dmsetup ls --tree
Example Output:
debian--vg-root (253:0)
├─ (254:17)
└─ (254:5)
debian--vg-swap_1 (253:1)
└─ (254:5)
1.2. Then re-run the command:
lvresize -l +$PESIZE /dev/mapper/debian--vg-root
[2]
resize2fs 1.42.9 (28-Dec-2013)
resize2fs: Bad magic number in super-block while trying to open /dev/mapper/centos-root
Couldn't find valid filesystem superblock.
2.1. try the following command
fsadm resize /dev/mapper/debian-root
