Ryfujk

The other answered provided do not address your question, I've identified the correct command to rescan an already connected disk.

We must rescan your already connected disk, first identify which disk you want to rescan.

ls /sys/class/scsi_disk/

In my example, I see a symlink named 0:0:0:0, so we rescan this scsi-disk.

echo '1' > /sys/class/scsi_disk/0:0:0:0/device/rescan

I just extended my VMware disk also, and had to scour other answers to find the correct command. Hopefully this will save future searchers from futile attempts.

As far as the root file system / is mounted on the disk that has been resized, the partition table and disk size are not refreshed by a SCSI rescan with Linux 2.6.26.

I really hope it will be better soon with newer kernel versions.

So I had to:

• reboot a first time to see the new disk size in fdisk
  


• delete the old primary PV partion in fdisk
  


• create a partition entry with the same number and start sector until the end of disk


• reboot a second time OR run partprobe from parted package only if / is not mounted there


• Now I can run pvresize to get new free space, lvextend and resize2fs to allocate some more space to a file system

I have been recommended to simply discard that stupid old partition table and run pvcreate directly on the device as Grub2 is able to load a kernel image directly from a file system on a LVM partition. But such a setup is not obvious at all with distribution installers.

Update: I have just checked with Debian GNU/Linux Jessie 8.2 running kernel 3.16 and parted 3.2, the partprobe now succeeds after partition table edition with cfdisk with no reboot. pvresize works immediately after.

If you want to extend a PV stored as logical PC partition, for instance /dev/sda5 on extended primary partition /dev/sda2, do not use fdisk but prefer parted:

parted /dev/sda2 -1

parted /dev/sda5 -1

pvresize /dev/sda5

You need to rescan the disks before you can make the bigger partition.

In Centos you can do this by

ls /sys/class/scsi_host

then for each host

echo "- - -" > /sys/class/scsi_host/host#/scan

(replace # with the number)

There is also one more step to the above which is expanding ext or whatever filesystem you are using once you have resized the partition.

You are still going to have to unmount that partition though at some point. What we tend to do is add a 2nd vmware disk and use lvm to extend onto the new disk (and reduce off the old if it is a replacement) as this allows the whole process to happen live.

You've not provided us enough detail to tell you the exact commands you'll need but essentially you'll need to use the lvextend command to extend the logical volume, then the e2fsck command and then the resize2fs command to actually expand your filesystem. Each of these commands will need additional parameters, specifically device and filesystem information, that we can't provide but you'll need to know these, just use the --help option for each command to tell you how to use them specifically, plus you'll probably end up using the pvdisplay, lvdisplay and mount commands to help fill out these parameters.

As an updated answer, on Ubuntu 16.04.1 I was able to do the following to resize a volume from 1024GB to 1.4TB:

echo '1' > /sys/class/scsi_disk/32:0:1:0/device/rescan

pvresize /dev/sdb

lvextend -l +100%FREE /dev/nvr01-opt/opt

resize2fs /dev/nvr01-opt/opt

No fdisk required, and the space was immediately available.

No one has posted a complete set of commands, so here we go:

# the following steps are for adding a new HDD

apt install scsitools

rescan-scsi-bus

pvcreate /dev/sdX

vgextend /dev/vgname /dev/sdx

lvextend -l +100%FREE /dev/vgname/root 

resize2fs /dev/vgname/root



#if resizing existing HDD

fdisk /dev/sdX

create new partition

pvcreate /dev/sdXn

vgextend /dev/vgname /dev/sdXn

lvextend -l +100%FREE /dev/vgname/root 

resize2fs /dev/vgname/root

This can help you :

https://www.thegeekdiary.com/centos-rhel-how-to-extend-physical-volume-in-lvm-by-extending-the-disk-partition-used/

https://theducks.org/2009/11/expanding-lvm-partitions-in-vmware-on-the-fly/

Let me now if you need some help