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King David
Asked: 2024-08-06 05:34:06 +0800 CST

Linux + how to increase partitions based on disk size

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we have some red-hat servers with the following details ( when OS disk size is 230G )

# lsblk
NAME             MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda                8:0    0  230G  0 disk
├─sda1             8:1    0    1G  0 part /boot/efi
├─sda2             8:2    0    1G  0 part /boot
└─sda3             8:3    0  228G  0 part
  ├─VG100-lv_root 253:0    0   20G  0 lvm  /
  ├─VG100-lv_swap 253:1    0   16G  0 lvm  [SWAP]
  └─VG100-lv_var  253:2    0   30G  0 lvm  /var


fdisk -l

Disk /dev/sda: 193.3 GB, 193273528320 bytes, 377487360 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x00000000

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1   209715199   104857599+  ee  GPT

the Goal is to increase the /var and root filesystem based on that disk size is 230G when current /var is 30G and root filesystem is 20G

so, we start with the following procedure that should gives us enough PFREE or enough “Physical Free” space.

parted /dev/sda resizepart 3 100%
Error: The backup GPT table is not at the end of the disk, as it should be.  This might mean that another operating system believes the disk is smaller.  Fix, by moving the backup to the end (and removing the old backup)?
parted: invalid token: 3
Fix/Ignore/Cancel?


sgdisk -e /dev/sda

note - sgdisk: The simplest way to fix the backup GPT table is by using the sgdisk command with the -e option, which moves the backup GPT data structures to the end of the disk

parted /dev/sda resizepart 3 100%
Information: You may need to update /etc/fstab.

partprobe /dev/sda

pvresize /dev/sda
  Failed to find physical volume "/dev/sda".
  0 physical volume(s) resized or updated / 0 physical volume(s) not resized

but from pvs Pfree is still 0

# pvs
  PV         VG   Fmt  Attr PSize  PFree
  /dev/sda3  VG100 lvm2 a--  66.00g    0

any idea about other approach that able to increase the /var and root filesystem partitions?

more info

# vgs
  VG   #PV #LV #SN Attr   VSize    VFree
  VG100  1   3   0 wz--n- <228.00g <162.00g

we also try this ( for example )

lvextend -l +100%FREE -r /dev/mapper/VG100-lv_root
  Size of logical volume VG100/lv_root unchanged from 20.00 GiB (5120 extents).
  Logical volume VG100/lv_root successfully resized.

xfs_growfs /dev/mapper/VG100-lv_root

but the size of root filesystem is the same

df -h | grep VG100-lv_root
/dev/mapper/VG100-lv_root   20G  3.8G   17G  19% /

 pvs
  PV         VG   Fmt  Attr PSize  PFree
  /dev/sda3  VG100 lvm2 a--  66.00g    0
linux

2 Answers

  1. Best Answer

    With the commands above you try to extend the partitions. And your partitions already allocate entire disks. Seems like you want to extend the logical volume which is mounted as root (/). To do this you need to execute the command:

    lvextend -l +100%FREE -r /dev/mapper/VG100-lv_root

    This will extend VG100-lv_root volume to use the entire free space from VG. Also -r will extend the filesystem.

    But my strong recommendation is to be more moderate and add for example 20-30GB to the volume and keep the rest of the space unused. And only in case of need extend the volumes. As this command (above) can be run on mounted filesystem and will work on the fly you do not need to care about downtime. From other side if you want to shrink / you need to boot from live CD, shrink filesystem and then shrink volume (so you have downtime). And some filesystems can't be shrinked (like XFS for example).

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  2. Since your disk is partitioned, and the LVM PV is sda3, you must use that device in your pvresize command instead of just sda:

    pvresize /dev/sda3

    Your pvresize /dev/sda told you it failed to achieve anything:

    pvresize /dev/sda
  Failed to find physical volume "/dev/sda".
  0 physical volume(s) resized or updated / 0 physical volume(s) not resized

    This is because the whole-disk device sda is not a LVM PV, and cannot possibly be made as such, as the disk needs to be a UEFI-bootable system disk.

    After a successful pvresize, the pvs command should show a non-zero PFree value, and then the lvextend commands can succeed.

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