This page describes how to increase the size of the various xfs LVM's on a CentOS7 desktop which uses LVM and xfs filesystems. In this case, I had purchased a laptop with a small 500Gb HDD and after I setup my complete CentOS system with source builds of LXC, OpenvSwitch and SCST, and had installed and confgured dynamic DNS/DHCP, I decided that I wanted to have (a) a copy of this fully-configured disk, and (b) have that copy on a much larger disk. So I found the largest 7mm laptop HD on Amazon which is a Seagate 5400 RPM 2Tb 7mm drive (granted a slow beast) and then I used Ubuntu install disk and booted into that Ubuntu disk to do a dd copy of the old disk to the new larger disk (example "dd if=/dev/sda of=/dev/sdb bs=128M").
After I was done with that, I put the new larger copy of the HDD into the original Lenovo ThinkPad P70 laptop and booted up with Gparted disk, and extended the 500Gb partition to the end of the 2Tb device giving me another 1.5 Tb or so of available space.
jNext boot up the laptop and now it's necessary to dole out that extra 1.5 Tb or so of space to the CentOS filesystem xfs filesystems in LV's, and that's what this guide is for to remind me how that was done when it's necessary to do that.
Here's an example of the kind of filesystem setup this guide covers as shown below.
[root@stlns01 ~]# df -TH
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/centos-root xfs 54G 6.3G 48G 12% /
devtmpfs devtmpfs 34G 0 34G 0% /dev
tmpfs tmpfs 34G 164k 34G 1% /dev/shm
tmpfs tmpfs 34G 9.5M 34G 1% /run
tmpfs tmpfs 34G 0 34G 0% /sys/fs/cgroup
/dev/sda1 xfs 518M 226M 293M 44% /boot
/dev/mapper/centos-home xfs 438G 682M 437G 1% /home
tmpfs tmpfs 6.7G 13k 6.7G 1% /run/user/1000
[root@stlns01 ~]#
Extend the LV as shown below. My reference for this was here.
[root@stlns01 ~]# lvextend -L60G /dev/centos/root
Size of logical volume centos/root changed from 50.00 GiB (12800 extents) to 60.00 GiB (15360 extents).
Logical volume root successfully resized.
[root@stlns01 ~]#
The filesystem should be the same size because it has not been grown yet even though the LV has already been extended.
[root@stlns01 ~]# df -TH
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/centos-root xfs 54G 6.3G 48G 12% /
devtmpfs devtmpfs 34G 0 34G 0% /dev
tmpfs tmpfs 34G 164k 34G 1% /dev/shm
tmpfs tmpfs 34G 9.5M 34G 1% /run
tmpfs tmpfs 34G 0 34G 0% /sys/fs/cgroup
/dev/sda1 xfs 518M 226M 293M 44% /boot
/dev/mapper/centos-home xfs 438G 682M 437G 1% /home
tmpfs tmpfs 6.7G 13k 6.7G 1% /run/user/1000
[root@stlns01 ~]#
[root@stlns01 ~]# xfs_growfs /
meta-data=/dev/mapper/centos-root isize=256 agcount=4, agsize=3276800 blks
= sectsz=4096 attr=2, projid32bit=1
= crc=0 finobt=0
data = bsize=4096 blocks=13107200, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=0
log =internal bsize=4096 blocks=6400, version=2
= sectsz=4096 sunit=1 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 13107200 to 15728640
[root@stlns01 ~]#
Check the output of the following commands as shown below.
[root@stlns01 ~]# pvdisplay
--- Physical volume ---
PV Name /dev/sda2
VG Name centos
PV Size 1.82 TiB / not usable 3.00 MiB
Allocatable yes
PE Size 4.00 MiB
Total PE 476806
Free PE 355153
Allocated PE 121653
PV UUID gxYGbp-5QSG-v2gc-2W2P-fm74-P9bL-o0D02V
[root@stlns01 ~]# vgdisplay
--- Volume group ---
VG Name centos
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 6
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 3
Open LV 3
Max PV 0
Cur PV 1
Act PV 1
VG Size 1.82 TiB
PE Size 4.00 MiB
Total PE 476806
Alloc PE / Size 121653 / 475.21 GiB
Free PE / Size 355153 / 1.35 TiB
VG UUID Pt0wBI-bQrK-uvlQ-KPp5-YlJd-7tUu-5nJfNt
[root@stlns01 ~]# lvdisplay
--- Logical volume ---
LV Path /dev/centos/root
LV Name root
VG Name centos
LV UUID KkLnrg-UeeS-BO6U-N5hA-3okg-gyNi-ftvQFH
LV Write Access read/write
LV Creation host, time localhost.localdomain, 2016-08-13 00:05:20 -0500
LV Status available
# open 1
LV Size 60.00 GiB
Current LE 15360
Segments 2
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:0
--- Logical volume ---
LV Path /dev/centos/home
LV Name home
VG Name centos
LV UUID pgn4Be-ZiGv-vaxh-bUz4-UVvP-H26m-wNcaeZ
LV Write Access read/write
LV Creation host, time localhost.localdomain, 2016-08-13 00:05:20 -0500
LV Status available
# open 1
LV Size 407.58 GiB
Current LE 104341
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:2
--- Logical volume ---
LV Path /dev/centos/swap
LV Name swap
VG Name centos
LV UUID re0udb-ePma-lYH2-P0ck-WBAz-OSCf-vp2pM1
LV Write Access read/write
LV Creation host, time localhost.localdomain, 2016-08-13 00:05:23 -0500
LV Status available
# open 2
LV Size 7.62 GiB
Current LE 1952
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:1
[root@stlns01 ~]#
That's all there was to it. Note that xfs filesystems cannot be "shrunk" in any straigtforward easy was like this as there is no shrink equivalent command for xfs filesystems similar to "xfs_growfs". Therefore, only growth is readily possible without much more involved measures.
There is a nice writeup on how to shrink an xfs filesystem here.