Editing LVM operations

== create LV == 
 1. create disk partition (fdisk)
 2. pvcreate /dev/sdb1
 3. lvmdiskscan , pvdisplay , pvscan(to check)
 4. vgcreate vg_newlvm /dev/sdb1
    vgcreate vg_newlvm /dev/sdb1 /dev/sdc1 
 5. lvcreate --name centos7_newvol -l 100%FREE vg_newlvm
    lvcreate -L 15G vg_newlvm
    lvcreate -l 50%VG -n centos7_newvol vg_newlvm
 6. lvdisplay (to check)
 7. mkfs.ext4 /dev/vg_newlvm/centos7_newvol
 
==resize LV == 

 1. Identify the Volume Group
    vgs
 2. Extend the Volume Group
    vgextend myvolume /dev/sda2
 3. Check
    vgs , vgdisplay
 4. Extend the Logical Volume
    lvextend -l +100%FREE /dev/myvg/myvolume
 Note: You can also extend the file system size using single lvextnd command by adding -r at end, example is shown below
    lvextend -l +100%FREE /dev/myvg/myvolume -r
 5. Extend the filesystem
    xfs_growfs /dev/myvg/myvolume

==disable/delete LV ==
 1. Delete the entry of the mount point from the /etc/fstab :
 # cat /etc/fstab
 ...
 /dev/mapper/datavg-testlv            /data01              ext4    defaults        0 0
 ...
 2. Unmount the mount point : 
 # umount /data01
 
 3. Disable lvm :
 # lvchange -an /dev/datavg/testlv
 
 4. Delete lvm volume :
 # lvremove /dev/datavg/testlv
 
 5. Disable volume group :
 # vgchange -an datavg
 
 6. Delete volume group :
 # vgremove datavg
 
 7. Delete physical Volumes being used for the volume group “datavg” :
 # pvremove /dev/sdb  /dev/sdc


==mount LVM from external disk ==

 Make sure lvm2 is installed:
 
 $ sudo yum install lvm2
 Load the necessary module(s) as root:
 
 $ sudo modprobe dm-mod
 Scan your system for LVM volumes and identify in the output the volume group name that has your Fedora volume (mine proved to be VolGroup00):
 
 $ sudo vgscan
 Activate the volume:
 
 $ sudo vgchange -ay VolGroup00
 Find the logical volume that has your Fedora root filesystem (mine proved to be LogVol00):
 
 $ sudo lvs
 Create a mount point for that volume:
 
 $ sudo mkdir /mnt/fcroot
 Mount it:
 
 $ sudo mount /dev/VolGroup00/LogVol00 /mnt/fcroot -o ro,user
 You're done, navigate to /mnt/fcroot and copy the files and paste somewhere else.
 
 Note: In case of bad sectors on the disk, one can prevent journaling with the option noload.