HowTo Resize The "root" File System Using LVM
Overview
This page demonstrates how to resize the root file system by increasing it's size by 2GB using the Logical Volume Manager (LVM). This will be done without rebooting the NST system. The follow environment exists:
- The root file system is under LVM control shown using the System Storage Manager (ssm):
[root@nst22 ~]# ssm list; ----------------------------------------------------------- Device Free Used Total Pool Mount point ----------------------------------------------------------- /dev/sda 20.00 GB PARTITIONED /dev/sda1 500.00 MB /boot /dev/sda2 0.00 KB 19.51 GB 19.51 GB nst22 ----------------------------------------------------------- ------------------------------------------------- Pool Type Devices Free Used Total ------------------------------------------------- nst22 lvm 1 0.00 GB 19.51 GB 19.51 GB ------------------------------------------------- ------------------------------------------------------------------------------------ Volume Pool Volume size FS FS size Free Type Mount point ------------------------------------------------------------------------------------ /dev/nst22/root nst22 17.51 GB xfs 17.50 GB 5.88 GB linear / /dev/nst22/swap nst22 2.00 GB linear /dev/sda1 500.00 MB ext4 500.00 MB 288.89 MB part /boot ------------------------------------------------------------------------------------
- The root file sytem is of type xfs
[root@nst22 ~]# mount | grep root; /dev/mapper/nst22-root on / type xfs (rw,relatime,attr2,inode64,noquota)
Demonstration
We will now show a sequence of commands to accomplish resizing the root file system by 2GB. Our NST system is a Virtual Machine (VM) running under the VMware Fusion Hypervisor. Behind the scenes we created a new virtual disk of size 2GB (/dev/sdb). On a physical system we could of used a whole disk or a disk partition for this demonstration.
The root file system size is currently 17.50GB in the Volume Group pool: "nst22". Our goal is to increase the root file system to a total of 19.50GB.
Initialize Disk or Disk Partition for LVM Usage
One can either us a whole disk or a disk partion for LVM:
- To use a disk partition: Use a partition tool (fdisk, cfdisk, gparted, etc...) to create the disk partition for LVM.
- To use the whole disk: Make sure the partition table is cleared out:
dd if=/dev/zero of=/dev/sdb bs=512 count=1
We will use the entire disk (/dev/sdb) for LVM using the following pvcreate command to initialize a Physical Volume:
pvcreate /dev/sdb;
Add the Physical Volume To An Existing Volume Group
We will now add (extend) the newly created Physical Volume: /dev/sdb to the nst22 Volume Group.
vgextend 'nst22' /dev/sdb;
We can validate the results of using the vgextend command above using pvscan and ssm list:
[root@nst22 tmp]# pvscan; PV /dev/sda2 VG nst22 lvm2 [19.51 GiB / 0 free] PV /dev/sdb VG nst22 lvm2 [2.00 GiB / 2.00 GiB free] Total: 2 [21.50 GiB] / in use: 2 [21.50 GiB] / in no VG: 0 [0 ]
[root@nst22 tmp]# ssm list; ----------------------------------------------------------- Device Free Used Total Pool Mount point ----------------------------------------------------------- /dev/sda 20.00 GB PARTITIONED /dev/sda1 500.00 MB /boot /dev/sda2 0.00 KB 19.51 GB 19.51 GB nst22 /dev/sdb 2.00 GB 0.00 KB 2.00 GB nst22 ----------------------------------------------------------- ------------------------------------------------- Pool Type Devices Free Used Total ------------------------------------------------- nst22 lvm 2 2.00 GB 19.51 GB 21.50 GB ------------------------------------------------- ------------------------------------------------------------------------------------ Volume Pool Volume size FS FS size Free Type Mount point ------------------------------------------------------------------------------------ /dev/nst22/root nst22 17.51 GB xfs 17.50 GB 5.88 GB linear / /dev/nst22/swap nst22 2.00 GB linear /dev/sda1 500.00 MB ext4 500.00 MB 288.89 MB part /boot
Resize The root File System
We now have unused disk under LVM control in the nst22 Volume Group pool to add to the root file system. We will accomplish the resizing of root without unmounting or rebooting using the following lvextend command (-r option):
[root@nst22 tmp]# lvextend -l "+100%PVS" -r /dev/nst22/root /dev/sdb;
Size of logical volume nst22/root changed from 17.51 GiB (4482 extents) to 19.50 GiB (4993 extents).
Logical volume root successfully resized
meta-data=/dev/mapper/nst22-root isize=256 agcount=4, agsize=1147392 blks
= sectsz=512 attr=2, projid32bit=1
= crc=0 finobt=0 spinodes=0
data = bsize=4096 blocks=4589568, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=0
log =internal bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 4589568 to 5112832
The validation of this demonstration for resizing of the root file system by 2GB is now shown:
[root@nst22 tmp]# df -h; Filesystem Size Used Avail Use% Mounted on devtmpfs 477M 0 477M 0% /dev tmpfs 488M 4.0K 488M 1% /dev/shm tmpfs 488M 1.1M 487M 1% /run tmpfs 488M 0 488M 0% /sys/fs/cgroup /dev/mapper/nst22-root 20G 12G 7.9G 60% / tmpfs 488M 8.0K 488M 1% /tmp /dev/sda1 477M 163M 285M 37% /boot tmpfs 98M 0 98M 0% /run/user/0 [root@nst22 tmp]# ssm list; ----------------------------------------------------------- Device Free Used Total Pool Mount point ----------------------------------------------------------- /dev/sda 20.00 GB PARTITIONED /dev/sda1 500.00 MB /boot /dev/sda2 0.00 KB 19.51 GB 19.51 GB nst22 /dev/sdb 0.00 KB 2.00 GB 2.00 GB nst22 ----------------------------------------------------------- ------------------------------------------------- Pool Type Devices Free Used Total ------------------------------------------------- nst22 lvm 2 0.00 KB 21.50 GB 21.50 GB ------------------------------------------------- ------------------------------------------------------------------------------------ Volume Pool Volume size FS FS size Free Type Mount point ------------------------------------------------------------------------------------ /dev/nst22/root nst22 19.50 GB xfs 19.49 GB 7.88 GB linear / /dev/nst22/swap nst22 2.00 GB linear /dev/sda1 500.00 MB ext4 500.00 MB 288.89 MB part /boot ------------------------------------------------------------------------------------ [root@nst22 tmp]# pvscan; PV /dev/sda2 VG nst22 lvm2 [19.51 GiB / 0 free] PV /dev/sdb VG nst22 lvm2 [2.00 GiB / 0 free] Total: 2 [21.50 GiB] / in use: 2 [21.50 GiB] / in no VG: 0 [0 ]
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