I have reduced the remove the RAID-1 array (/dev/md0) to 48G size and it is configured on the lvm and trying to reduce respective disk space (sda4) as well to 48G from 58G.

But i am not able to accomplish this, could you please help me regarding this.

root@sekhar~# lsblk
NAME                    MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT
sda                       8:0    0 232.9G  0 disk
├─sda1                    8:1    0  16.5G  0 part
└─sda4                    8:4    0    58G  0 part
  └─md0                   9:0    0    48G  0 raid1
    ├─vg0-root (dm-0)   252:0    0  26.6G  0 lvm   /
    ├─vg0-backup (dm-1) 252:1    0  19.6G  0 lvm
    └─vg0-swap (dm-2)   252:2    0   1.9G  0 lvm   [SWAP]
sr0                      11:0    1  1024M  0 rom

root@sekhar~:~# pvdisplay
  --- Physical volume ---
  PV Name               /dev/md0
  VG Name               vg0
  PV Size               48.00 GiB / not usable 3.00 MiB
  Allocatable           yes (but full)
  PE Size               4.00 MiB
  Total PE              12287
  Free PE               0
  Allocated PE          12287
  PV UUID               uxH3FS-sUOF-LsIP-kAjq-7Bwq-suhK-CLJXI1

root@sekhar~:~# vgdisplay
  --- Volume group ---
  VG Name               vg0
  System ID
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  112
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                3
  Open LV               2
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               48.00 GiB
  PE Size               4.00 MiB
  Total PE              12287
  Alloc PE / Size       12287 / 48.00 GiB
  Free  PE / Size       0 / 0
  VG UUID               LjCUyX-25MQ-WCFT-j2eF-2UWX-LYCp-TtLVJ5

root@sekhar~:~# lvdisplay
  --- Logical volume ---
  LV Path                /dev/vg0/root
  LV Name                root
  VG Name                vg0
  LV UUID                SBf1mc-iqaB-noBx-1neo-IEPi-HhsH-SM14er
  LV Write Access        read/write
  LV Creation host, time S000001, 2015-09-23 03:01:19 +0000
  LV Status              available
  # open                 1
  LV Size                26.59 GiB
  Current LE             6808
  Segments               2
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           252:0

  --- Logical volume ---
  LV Path                /dev/vg0/backup
  LV Name                backup
  VG Name                vg0
  LV UUID                E0zuBR-3iIT-ig42-1y2j-YvJY-PMea-P9d8D4
  LV Write Access        read/write
  LV Creation host, time S000001, 2017-02-11 05:30:02 +0000
  LV Status              available
  # open                 0
  LV Size                19.54 GiB
  Current LE             5003
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           252:1

  --- Logical volume ---
  LV Path                /dev/vg0/swap
  LV Name                swap
  VG Name                vg0
  LV UUID                LqeFep-zKvG-vRJI-Id9N-LXmZ-FZlI-fvM040
  LV Write Access        read/write
  LV Creation host, time Microknoppix, 2017-03-02 16:09:29 +0000
  LV Status              available
  # open                 2
  LV Size                1.86 GiB
  Current LE             476
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           252:2

root@sekhar~:~# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid1 sda4[3]
      50331648 blocks super 1.2 [2/1] [U_]

unused devices: 

Dibs,

You are quite welcome and best of luck on the LCFS. It’s a great test to challenge yourself with common Linux tasks!

Anders, To each their own. /mnt was only used for illustrative purposes. The box that these drives are actually in, does mount the LVM’s in a different location.