Linux Tutorials - Herong's Tutorial Examples - v5.45, by Herong Yang
Extend /home LV with a New Partition
This section provides a tutorial example on how to extend the /home file system on a LV (Logical Volume) on the fly with an newly added PV (Physical Volume) on the VG (Volume Group).
How To Extend /home LV? By default CentOS 8 uses a LV (Logical Volume) for /home directory. If /home is running out of space, you can easily extend the LV by adding a new partition to the VG (Volume Group).
1. Check current usage of /home. I see only 23% free space left.
herong$ df -m Filesystem 1M-blocks Used Available Use% Mounted on /dev/mapper/cl-root 51175 6133 45043 12% / /dev/mapper/cl-home 39857 30595 9262 77% /home ...
2. Find the VG that hosts the /home LV. I see "cl" as the VG name.
herong$ sudo lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log home cl -wi-ao---- 38.94g root cl -wi-ao---- 50.00g swap cl -wi-ao---- 7.71g
3. Check the usage of the "cl" VG. I see 0 free space left.
herong$ sudo vgs VG #PV #LV #SN Attr VSize VFree cl 1 3 0 wz--n- 96.65g 0
4. Check the usage the second hard disk /dev/sdb. I see 2000GB free space left.
herong$ sudo parted /dev/sdb print free
Number Start End Size File system Name Flags
17.4kB 1049kB 1031kB Free Space
1 1049kB 2000GB 2000GB ext4 primary
2000GB 4000GB 2000GB Free Space
5. Create a new partition of 1000GB on /dev/sdb as a new PV (Physical Volume). I see /dev/sdb2 ready as a partition.
herong$ sudo parted /dev/sdb mkpart primary ext4 2000GB 3000GB
Information: You may need to update /etc/fstab.
herong$ sudo parted /dev/sdb print free
Number Start End Size File system Name Flags
17.4kB 1049kB 1031kB Free Space
..
1 1049kB 2000GB 2000GB ext4 primary
2 2000GB 3000GB 1000GB primary
3000GB 4000GB 1000GB Free Space
6. Convert /dev/sdb2 into a new PV with "pvcreate" command. I see /dev/sdb2 ready as PV.
herong$ sudo pvcreate /dev/sdb2 Physical volume "/dev/sdb3" successfully created. herong$ sudo pvs PV VG Fmt Attr PSize PFree /dev/sda7 cl lvm2 a-- 96.65g 0 /dev/sdb2 lvm2 a-- 931.69g 831.69g
7. Add /dev/sdb2 as a PV to "c1" VG with "vgextend" command. I see "c1" VG with 924.82g free space now.
herong$ sudo vgextend cl /dev/sdb2 Volume group "cl" successfully extended herong$ sudo vgs VG #PV #LV #SN Attr VSize VFree cl 3 3 0 wz--n- 1.10t 924.82g
8. Find the device path for /home LV. I see /dev/cl/home.
herong$ sudo lvdisplay --- Logical volume --- LV Path /dev/cl/home LV Name home VG Name cl LV UUID GTeo46-cl6I-XFL8-tCvb-vCeN-swL7-lyCV2n LV Write Access read/write LV Creation host, time localhost, 2020-03-27 05:01:49 +0800 LV Status available # open 1 LV Size 38.94 GiB Current LE 9969 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:2
8. Extend /home LV with an extra 100GB with "lvextend" command.
herong$ sudo lvextend /dev/cl/home -L +100G
Size of logical volume cl/home changed from 38.94 GiB (9969 extents)
to 138.94 GiB (35569 extents).
Logical volume cl/home successfully resized.
9. Check storage spaces of all LVs with "lvscan" command. I see an extra 100GiB added to /dev/cl/home.
herong$ sudo lvscan ACTIVE '/dev/cl/swap' [7.71 GiB] inherit ACTIVE '/dev/cl/home' [138.94 GiB] inherit ACTIVE '/dev/cl/root' [50.00 GiB] inherit
10. Check file system usage on /home. I see no changes, because the file system on /dev/cl/home is not extended yet.
herong$ df -m Filesystem 1M-blocks Used Available Use% Mounted on /dev/mapper/cl-root 51175 6133 45043 12% / /dev/mapper/cl-home 39857 30595 9262 77% /home ...
11. Extent the file system on /dev/cl/home to the end of the LV "partition" with "resize2fs" command. I see an error, because "resize2fs" command supports ext2/3/4 file system types only.
herong$ sudo resize2fs /dev/cl/home resize2fs 1.44.6 (5-Mar-2019) resize2fs: Bad magic number in super-block while trying to open /dev/cl/home Couldn't find valid filesystem superblock.
12. Check the file system type on /dev/cl/home with "file -s" command. I see "SGI XFS" file system type.
herong$ sudo file -s /dev/cl/home /dev/cl/home: symbolic link to ../dm-2 herong$ sudo file -s /dev/dm-2 /dev/dm-2: SGI XFS filesystem data (blksz 4096, inosz 512, v2 dirs)
13. Try to extent the file system on /dev/cl/home to the end of the LV "partition" with "xfs_growfs" command. I see an error, because "xfs_growfs" command takes the mounting point /home as its argument, instead of the device file name.
herong$ sudo xfs_growfs /dev/cl/home xfs_growfs: /dev/cl/home is not a mounted XFS filesystem
14. Extent the mounted /home to the end of the LV "partition" with "xfs_growfs" command. I see no errors.
herong$ sudo xfs_growfs /home
meta-data=/dev/mapper/cl-home isize=512 agcount=4, agsize=2552064 blks
= sectsz=4096 attr=2, projid32bit=1
= crc=1 finobt=1, sparse=1, rmapbt=0
= reflink=1
data = bsize=4096 blocks=10208256, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0, ftype=1
log =internal log bsize=4096 blocks=4984, version=2
= sectsz=4096 sunit=1 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 10208256 to 36422656
15. Confirm the storage usage of /home. I see only 78% free space now.
herong$ df -m Filesystem 1M-blocks Used Available Use% Mounted on /dev/mapper/cl-root 51175 13743 37433 27% / /dev/mapper/cl-home 142257 30595 113683 22% /home ...
Cool. I have successfully extended the /home LV with a new partition added to the VG on the fly with /home still in use. If you want to be on the safer side, disconnect all users, stop all applications that are using /home. Take a backup of /home files, and then follow above steps.
Table of Contents
Cockpit - Web Portal for Administrator
What Is LVM (Logical Volume Manager)
Create New PV (Physical Volume)
Add/Remove PV on VG on the Fly
►Extend /home LV with a New Partition
SELinux - Security-Enhanced Linux
SSH Protocol and ssh/scp Commands
Software Package Manager on CentOS - DNF and YUM
vsftpd - Very Secure FTP Daemon