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# Tested on RHEL 6 & 7
# *** I recommend to backup all important data before carrying out an operation like the # one described here. # I carried out my RHEL installation without being careful about disk partitioning. Now I # don't have any space to create an additional Volume Group on system disk (I don' have # any other available disks) and, the worst, there's a lot of wasted GBs as my system disk # is about 136GB and I'm only using some 18GB for the OS filesystems: pvs PV VG Fmt Attr PSize PFree /dev/sda2 rootvg lvm2 a-- 135.72g 117.72g lvs LV VG Attr LSize Pool Origin Data% Move Log Cpy%Sync Convert lv_home rootvg -wi-ao---- 2.00g lv_opt rootvg -wi-ao---- 2.00g lv_root rootvg -wi-ao---- 1.00g lv_swap rootvg -wi-ao---- 4.00g lv_tmp rootvg -wi-ao---- 2.00g lv_usr rootvg -wi-ao---- 4.00g lv_var rootvg -wi-ao---- 3.00g # I decided to reduce root Volume Group down to 32GB in order to free up some disk space # This is the current partitioning /boot (ext4) rootvg |--------------|-----------------------------------------------------------| <-- 256 MB --> <---- rest of the disk, some 136 GB ----------------------> # And what I'd like to have /boot (ext4) rootvg free space |--------------|-----------------|-----------------------------------------| <-- 256 MB --> <---- 32 GB ----> <--------------- ~100 GB ---------------> # First of all, I check that all the existing volumes are in contiguous disk areas; at # least, that there is enough free space at the end of the physical volume as to reduce # it to the wished size. In my case everything seems good to do the required operations. # Otherwise we should have done some "move" operations on the logical volumes. lvm pvdisplay --maps --- Physical volume --- PV Name /dev/sda2 VG Name rootvg PV Size 135.72 GiB / not usable 3.00 MiB Allocatable yes PE Size 32.00 MiB Total PE 4343 Free PE 3767 Allocated PE 576 PV UUID tNLp0a-Hucs-Ic53-9PXH-6C1z-YRGX-t5eqy6 --- Physical Segments --- Physical extent 0 to 31: Logical volume /dev/rootvg/lv_root Logical extents 0 to 31 Physical extent 32 to 159: Logical volume /dev/rootvg/lv_usr Logical extents 0 to 127 Physical extent 160 to 223: Logical volume /dev/rootvg/lv_opt Logical extents 0 to 63 Physical extent 224 to 287: Logical volume /dev/rootvg/lv_home Logical extents 0 to 63 Physical extent 288 to 383: Logical volume /dev/rootvg/lv_var Logical extents 0 to 95 Physical extent 384 to 447: Logical volume /dev/rootvg/lv_tmp Logical extents 0 to 63 Physical extent 448 to 575: Logical volume /dev/rootvg/lv_swap Logical extents 0 to 127 Physical extent 576 to 4342: <----- FREE # Let's reduce the physical volume pvresize --setphysicalvolumesize 32G /dev/sda2 Physical volume "/dev/sda2" changed 1 physical volume(s) resized / 0 physical volume(s) not resized pvs PV VG Fmt Attr PSize PFree /dev/sda2 rootvg lvm2 a-- 31.97g 13.97g # and, then, the partition that contains the physical volume (regarding cylinders # boundaries, I did my calculations before) fdisk /dev/sda WARNING: DOS-compatible mode is deprecated. It's strongly recommended to switch off the mode (command 'c') and change display units to sectors (command 'u'). Command (m for help): p Disk /dev/sda: 146.0 GB, 145999527936 bytes 255 heads, 63 sectors/track, 17750 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x0007a6a0 Device Boot Start End Blocks Id System /dev/sda1 * 1 33 262144 83 Linux Partition 1 does not end on cylinder boundary. /dev/sda2 33 17751 142314496 8e Linux LVM Command (m for help): d Partition number (1-4): 2 Command (m for help): n Command action e extended p primary partition (1-4) p Partition number (1-4): 2 First cylinder (33-17750, default 33): Using default value 33 Last cylinder, +cylinders or +size{K,M,G} (33-17750, default 17750): 4211 Command (m for help): p Disk /dev/sda: 146.0 GB, 145999527936 bytes 255 heads, 63 sectors/track, 17750 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x0007a6a0 Device Boot Start End Blocks Id System /dev/sda1 * 1 33 262144 83 Linux Partition 1 does not end on cylinder boundary. /dev/sda2 33 4211 33561689+ 83 Linux Command (m for help): w The partition table has been altered! Calling ioctl() to re-read partition table. # Reboot, to load the new partition table shutdown -r now # And, finally, resize physical volume to match partition size pvresize /dev/sda2 Physical volume "/dev/sda2" changed 1 physical volume(s) resized / 0 physical volume(s) not resized pvs PV VG Fmt Attr PSize PFree /dev/sda2 rootvg lvm2 a-- 32.00g 14.00g |