I have CentOS7 with RAID0. by default the OS create three partitions so the 3rd partition is LVM. my goal is to decrease the size of the 3rd partition and create another VG.[root@localhost ~]# lsblkNAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTsda           8:0    0  7.3T  0 disksda1        8:1    0  200M  0 part /boot/efisda2        8:2    0    1G  0 part /bootsda3        8:3    0  7.3T  0 part  cl-root 253:0    0    2T  0 lvm  /  cl-swap 253:1    0    4G  0 lvm  [SWAP]  cl-home 253:2    0  150G  0 lvm  /homeused the command pvresize --setphysicalvolumesize 2.7T /dev/sda3 to shrink the virtual partition: [root@localhost ~]# pvs  PV         VG Fmt  Attr PSize PFree  /dev/sda3  cl lvm2 a--  2.70t 513.24gso the cl vg only used 2.7T and the total space of /dev/sda3 is 7.3T. I need to create with the 4.5T another vg.any opinions? thanks!
shrink /dev/sda3 and create another VG - centOS 7
centos;partition;raid;storage
pvresize can shrink the PV inside the partition, but you also need to shrink the partition.The simplest approach to shrink partitions containing PV's and other common Linux partition contents is to use a gparted boot disk.After shrinking the partition, I would boot back into the normal system.  Some (though not all) tools will warn you e.g. if you try to erase or reformat a mounted filesystem, so this can be useful.  Then simply run fdisk, use the n command, accept the default size and set the type to LVM PV.  Save the changes with the w command.  It should ask the kernel to rescan the partition table and print a success message.  Then pvcreate /dev/sda4 and vgcreate NewGroupName /dev/sda4.Without gparted, you have to very carefully use fdisk to remove the partition, then create a new partition with the reduced size, not smaller, making sure to  avoid problems with rounding and the 1024/1000 confusion (Tebibytes).  I believe you should reboot immediately once you've shrunk the partition, because the kernel will not re-reread the size of a partition which is currently in use.