How to increase the size for /dev/mapper/centos-root without data loss

I am running a virtual server, and the provider added extra diskspace. However, I need to somehow increase (merge) the existing disk (has data) and the new disk (empty).

how to increase the size for /dev/mapper/centos-root?

[root]#df -hFilesystem               Size  Used Avail Use% Mounted ondevtmpfs                 3.9G     0  3.9G   0% /devtmpfs                    3.9G     0  3.9G   0% /dev/shmtmpfs                    3.9G  243M  3.7G   7% /runtmpfs                    3.9G     0  3.9G   0% /sys/fs/cgroup/dev/mapper/centos-root   98G   83G   16G  85% /tmpfs                    3.9G  156K  3.9G   1% /tmp/dev/sda1                497M  168M  330M  34% /boottmpfs                    797M     0  797M   0% /run/user/1000[root]# fdisk -lDisk /dev/sda: 214.7 GB, 214748364800 bytes, 419430400 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk label type: dosDisk identifier: 0x000997be   Device Boot      Start         End      Blocks   Id  System/dev/sda1   *        2048     1026047      512000   83  Linux/dev/sda2         1026048    41943039    20458496   8e  Linux LVM/dev/sda3        41943040   209715199    83886080   8e  Linux LVMDisk /dev/mapper/centos-swap: 2147 MB, 2147483648 bytes, 4194304 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk /dev/mapper/centos-root: 104.7 GB, 104694022144 bytes, 204480512 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytes

It shows a total of > 200GB, so I do have 100GB extra (unused), so I tried to grow it from the Volume Group (VG), but it indicates there is no free space. So I guess I have to somehow add the free space to the VG first? Just how?

[root]# vgdisplay  --- Volume group ---  VG Name               centos  System ID  Format                lvm2  Metadata Areas        2  Metadata Sequence No  5  VG Access             read/write  VG Status             resizable  MAX LV                0  Cur LV                2  Open LV               2  Max PV                0  Cur PV                2  Act PV                2  VG Size               99.50 GiB  PE Size               4.00 MiB  Total PE              25473  Alloc PE / Size       25473 / 99.50 GiB  Free  PE / Size       0 / 0  VG UUID               mlGu82-tMEl-EB1I-LdvQ-V5Jz-FmRD-7wMPdk

Below you see how the LV is divided (between SWAP and ROOT)m guess that is pretty default.

[root]# lvdisplay  --- Logical volume ---  LV Path                /dev/centos/swap  LV Name                swap  VG Name                centos  LV UUID                E4q3BO-bxxu-Mj8J-nNYJ-ECdR-He20-UqTzHd  LV Write Access        read/write  LV Creation host, time localhost, 2017-07-12 03:09:26 +0700  LV Status              available  # open                 2  LV Size                2.00 GiB  Current LE             512  Segments               1  Allocation             inherit  Read ahead sectors     auto  - currently set to     8192  Block device           253:0  --- Logical volume ---  LV Path                /dev/centos/root  LV Name                root  VG Name                centos  LV UUID                fANu3W-nl0g-40rQ-NLSA-I77S-4vXE-Stg2D5  LV Write Access        read/write  LV Creation host, time localhost, 2017-07-12 03:09:27 +0700  LV Status              available  # open                 1  LV Size                97.50 GiB  Current LE             24961  Segments               2  Allocation             inherit  Read ahead sectors     auto  - currently set to     8192  Block device           253:1

Only in the CFDISK I can actually see there is free space on the same disk: sda

 cfdisk (util-linux 2.23.2)                              Disk Drive: /dev/sda                       Size: 214748364800 bytes, 214.7 GB             Heads: 255   Sectors per Track: 63   Cylinders: 26108    Name        Flags      Part Type  FS Type          [Label]        Size (MB) ------------------------------------------------------------------------------                            Pri/Log   Free Space                           1.05*    sda1        Boot        Primary   xfs                                524.29*    sda2                    Primary   LVM2_member                      20949.50*    sda3                    Primary   LVM2_member                      85899.35*                            Pri/Log   Free Space                      107374.19*

For Filesystems (read somewhere not all support resizing):

[root]# lsblk -fNAME            FSTYPE      LABEL UUID                                   MOUNTPOINTsda├─sda1          xfs               9b1d00b3-24f5-4c0e-b84a-d6d9527d375d   /boot├─sda2          LVM2_member       4rFgZ8-tAZH-8Mr0-hauE-vz9j-YCV4-3gVl3r│├─centos-swap swap              456e16d8-3c60-46b5-812a-3ae2d54f5bcf   [SWAP]│└─centos-root xfs               fa159170-1c29-4387-80c4-d168e2cc64c4   /└─sda3          LVM2_member       c6CKfP-RP63-F107-qJ7G-0lCC-0CJZ-pOKJ4x└─centos-root xfs               fa159170-1c29-4387-80c4-d168e2cc64c4   /

Also, the centos-root is referenced in the fstab:

/dev/mapper/centos-root /                       xfs     defaults        1 1

I hope I provided enough info to make a good assessment and I really I hope I can increase the disk without data loss, otherwise I have to find a way to transfer 100GB somewhere, and then delete all, and re-create a bigger disk. I am sure there is an easier way in 2022 :)

Thanks in advance!

PS. I did read similar posts of course, but it puzzled me even more. And I am just afraid to accidently remove the existing data (even though I have a backup).