My Centos6x64 VM came has a ~500G disk xvda. Initially, 8G was allocated to xvda1 and mounted on /. The remainder of the 500G disk space in xvda was not yet allocated. So i decided to make this remainder disk space usable and created a partition xvda2 with logical volumes using fdisk, pvcreate, vgcreate, lvcreate, formatting and finally updating fstab to mounted them automatically.
The relationships to the corresponding folders (mount point) is:
- /dev/centos/home ..../home [200G]
- /dev/centos/root ..../ [100G]
Problem is:
- The /home seem to have mounted correctly as size shown upon
df -h
is 197G. - But the mounting on root is not correct. In the results for
df -h
below, the size of/dev/xvda1
mounted on/boot
is 7.8G which is correct. But, the size of/dev/mapper/centos-root
mounted on/
incorrectly shows 7.8G. It should show approximately 100G. It is incorrectly showing the same disk space as that of/dev/xvda1
.
Questions:
- I have tried to collate some results below for your reference. Kindly help resolve this problem. What can i do to correct the problem?
- Also, if i just wanted to increase the disk space allocated to xvda1 from 8G to say 200G, is there a simpler more direct way? on googling, i found this post that very much matched the objective. But i could not get it to reboot successfully as it lay stuck on the grub screen. I don't have much info on this failure details. Could i have missed out some setup pre-requisites when using fdisk to allocate additional disk space eg: formatting?
I pretty much new on this and stuck. Please Kindly help.
Initial State of System:
# fdisk -l
Disk /dev/xvda: 536.9 GB, 536870912000 bytes 255 heads, 63 sectors/track, 65270 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000611ee
Device Boot Start End Blocks Id System
/dev/xvda1 * 1 1045 8387584 83 Linux
Disk /dev/xvdb: 32.2 GB, 32204390400 bytes 255 heads, 63 sectors/track, 3915 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000
# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda 202:0 0 500G 0 disk
└─xvda1 202:1 0 8G 0 part /
xvdb 202:16 0 30G 0 disk /mnt
# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/xvda1 7.8G 897M 6.5G 12% /
tmpfs 3.6G 0 3.6G 0% /dev/shm
/dev/xvdb 30G 173M 28G 1% /mnt
# cat /etc/fstab
UUID=2d0f2d55-672b-4c05-8eba-9421dd808ad7 / ext4 defaults 1 1
tmpfs /dev/shm tmpfs defaults 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
sysfs /sys sysfs defaults 0 0
proc /proc proc defaults 0 0
/dev/xvdb /mnt auto defaults,nofail,comment=cloudconfig 0 2
Steps i performed:
- fdisk /dev/xvda ...(n > p = 2 > t = 8e)
- reboot
- pvcreate /dev/xvda2
- vgcreate centos /dev/xvda2
- lvcreate -n home -L 200G centos
- lvcreate -n root -L 100G centos
- lvcreate -n swap -L 4G cent
- mkfs.ext4 /dev/centos/root
- mkfs.ext4 /dev/centos/home
- mkswap /dev/centos/swap
- mount /dev/xvda1 /boot
- ...This is what i want to do but was not permitted.
- So instead, i updated
/etc/fstab
and changed mount point for/dev/xvda1
from/
to/boot
. But this also does not work.
- In the results provided below,
df -h
shows the correct mount points for both/dev/xvda1 i.e. /boot
and/dev/mapper/centos-root i.e. /
but the disk space shown for/dev/mapper/centos-root = 7.8G
is incorrect. I was expecting~100G
.- Also, the results for
lsblk
shows empty mount point forcentos-root (dm-1)
. Forcentos-root
, i expected mount point/
and for/dev/xvda1
expected mount point/boot
.- mount /dev/centos/root /
- mount /dev/centos/home /home
- make corresponding entries into /etc/fstab (refer
cat /etc/fstab
below)- shutdown -r now
- mkhomedir_helper centos
- On reboot, home dir for centos became inaccessible and so i got error "Could not chdir to home directory /home/centos: No such file or directory". To resolve, I had to run the above command to recreate home directory for user centos
cat /etc/fstab
UUID=3a75c67b-5053-4863-963e-c6a572f13972 / ext4 defaults 1 1
UUID=2d0f2d55-672b-4c05-8eba-9421dd808ad7 /boot ext4 defaults 1 2
tmpfs /dev/shm tmpfs defaults 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
sysfs /sys sysfs defaults 0 0
proc /proc proc defaults 0 0
/dev/xvdb /mnt auto defaults,nofail,comment=cloudconfig 0 2
/dev/mapper/centos-home /home ext4 defaults 0 0
fdisk -l
Device Boot Start End Blocks Id System
/dev/xvda1 * 1 1045 8387584 83 Linux
/dev/xvda2 1045 65270 515892667 8e Linux LVM
df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/centos-root 7.8G 898M 6.5G 12% /
tmpfs 3.6G 0 3.6G 0% /dev/shm
/dev/xvda1 7.8G 898M 6.5G 12% /boot
/dev/xvdb 30G 173M 28G 1% /mnt
/dev/mapper/centos-home 197G 60M 187G 1% /home
lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda 202:0 0 500G 0 disk
├─xvda1 202:1 0 8G 0 part /
└─xvda2 202:2 0 492G 0 part
├─centos-home (dm-0) 253:0 0 200G 0 lvm /home
├─centos-root (dm-1) 253:1 0 100G 0 lvm
└─centos-swap (dm-2) 253:2 0 4G 0 lvm
xvdb 202:16 0 30G 0 disk /mnt
blkid
/dev/xvda1: UUID="2d0f2d55-672b-4c05-8eba-9421dd808ad7" TYPE="ext4"
/dev/xvdb: UUID="3656cb72-7e94-4e63-81ea-66397ad45d13" SEC_TYPE="ext2" TYPE="ext3"
/dev/xvda2: UUID="ASXeKh-x8xL-nDVF-afzq-zU8a-sCbd-qGM6pS" TYPE="LVM2_member"
/dev/mapper/centos-home: UUID="4510891a-354d-4486-bd47-95d474f197bb" TYPE="ext4"
/dev/mapper/centos-root: UUID="3a75c67b-5053-4863-963e-c6a572f13972" TYPE="ext4"
/dev/mapper/centos-swap: UUID="5dff9552-3d36-4cfa-936c-28e02c1ae108" TYPE="swap"
lvdisplay
--- Logical volume ---
LV Path /dev/centos/home
LV Name home
VG Name centos
LV UUID lFWQxa-mqgc-Ur8t-npDc-O2NU-r6J4-UhC2j2
LV Write Access read/write
LV Creation host, time ip-xx-xx-xx-xx.ec2.internal, 2018-06-16 07:18:22 +0000
LV Status available
# open 1
LV Size 200.00 GiB
Current LE 51200
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:0
--- Logical volume ---
LV Path /dev/centos/root
LV Name root
VG Name centos
LV UUID UQ6oAD-JyRa-cb8l-VmgW-aZh9-qbof-Z1Z9af
LV Write Access read/write
LV Creation host, time ip-xx-xx-xx-xx.ec2.internal, 2018-06-16 07:18:22 +0000
LV Status available
# open 0
LV Size 100.00 GiB
Current LE 25600
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:1
--- Logical volume ---
LV Path /dev/centos/swap
LV Name swap
VG Name centos
LV UUID QyY2z9-5EpX-D8dY-DORZ-9BbY-TqgA-07fc3X
LV Write Access read/write
LV Creation host, time ip-xx-xx-xx-xx.ec2.internal, 2018-06-16 07:18:24 +0000
LV Status available
# open 0
LV Size 4.00 GiB
Current LE 1024
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:2
df -h
andlsblk
are not in alignment. The former suggests/
is an LVM logical volume while the latter suggests it'sxvda1
; Did you update your GRUB config to specify your new/
block device? How did you populate your/
logical volume; Perhaps youdd
'ed the contents?xvda2
elsewhere because it contains the logical volumes including/home
andswap
.xvda1
to LVroot
of VGcentos
without rebooting, there may be some out-of-date information left in/etc/mtab
which might be confusing thedf
command. If necessary, you can actually docat /proc/mounts >/etc/mtab
to update it, since you don't seem to have anything complicated going on with mounts. Before rebooting, be sure to update your initramfs so it will be up to date with the new situation (seeman mkinitrd
).man mkinitrd
; @tonioc, @NasirRiley, All - will the updated description help? what can i do to allocate more disk space to/
. All:, i have updated the main description to include better clarity on initial state of system and the steps i performed. Hope this is helpful. Kindly help me out. Thanks a ton.