Can I extend a Centos 7 partition while preserving its contents

Question

I inherited managing a Centos 7 server where I am frequently running out of space in the root directory because its size is only 20Gb as shown bvelow.

df -h (excerpt)
/dev/sdb2                               20G   15G  5.4G  74% /
/dev/sdb5                               90G   25G   66G  28% /home
/dev/sdb1                              497M  212M  286M  43% /boot

What would be the safest and easiest way to expand this partition? Listed below is the partition table for /dev/sdb.

Device Boot      Start         End      Blocks   Id  System
  sdb1   *        2048     1026047      512000   83  Linux
  sdb2         1026048    42969087    20971520   83  Linux
  sdb3        42969088    59746303     8388608   82  Linux swap / Solaris
  sdb4        59746304   247463935    93858816    5  Extended
  sdb5        59748352   247463935    93857792   83  Linux

My thought is to move the /home directory to a logical partition on /dev/sda (different drive) which would free up space on /dev/sdb. Could I then on /dev/sdb:

• Delete partitions sdb3, sdb4 & sdb 5
• Extend partition sdb2 while preserving its content
• Recreate a new swap partition

Here are all of my partitions:

    lsblk
    
    sdb                             8:16     0   118G  0 disk
    ├─sdb1                          8:17     0   500M  0 part /boot
    ├─sdb2                          8:18     0    20G  0 part /
    ├─sdb3                          8:19     0     8G  0 part [SWAP]
    ├─sdb4                          8:20     0     1K  0 part
    └─sdb5                          8:21     0  89.5G  0 part /home
    
    sda                             8:0      0   5.5T  0 disk
    └─sda1                          8:1      0   5.5T  0 part
      ├─VG_part_1                   252:0    0   2.2T  0 lvm  /var/lib/app
      ├─VG_part_2                   252:1    0   250G  0 lvm  /var/log
      └─VG_part_3                   252:3    0   100G  0 lvm  /data
    

Answer 1

Yes, this is the right way to process:

1. create new LV for home, create filesystem, mount it somewhere
2. create new LV for swap, activate this swap
3. copy all the files from /home to new LV from point 1
4. unmount /home
5. remount LV home to /hoe and do extensive checks with users.
6. if point 5 is OK update /etc/fstab to point to LV home
7. deactivate swap on /dev/sdb3
8. remove /dev/sdb3 and /dev/sdb4
9. extend /dev/sdb2 and extend the filesystem
10. optionally create swap partition on /dev/sdb, activate it, etc.