Re: [CentOS] LVM

Done!

Attention: Shrink/Extend a filesystem may damage the data on it, pls backup date before.

1. Decrease /dev/mapper/vg_web-lv_home # umount /dev/mapper/vg_web-lv_home # e2fsck -f /dev/mapper/vg_web-lv_home # resize2fs /dev/mapper/vg_web-lv_home <size> # lvresize -L <size> /dev/mapper/vg0-lv_home # mount -o remount /home

check the size of /dev/mapper/vg_web-lv_home with "df -kh"

2. Increase /dev/mapper/vg_web-lv_root # lvresize -L <size> /vg_web-lv_root # resize2fs /vg_web-lv_root

check the size of /dev/mapper/vg_web-lv_root with "df -kh"

df -kh Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg_websdc-lv_root 296G 7.1G 274G 3% / tmpfs 7.8G 176K 7.8G 1% /dev/shm /dev/sda2 485M 84M 377M 19% /boot /dev/sda1 200M 256K 200M 1% /boot/efi /dev/mapper/vg_websdc-lv_home 99G 6.3G 88G 7% /home

Thanks.

On Tue, Mar 20, 2012 at 12:04 PM, Markus Falb markus.falb@fasel.at wrote:

On 19.3.2012 10:16, John R Pierce wrote:

...

On 03/19/12 2:14 AM, Peter Kjellström wrote:

...

I can also add that I've successfully managed to shrink ext3 before

but a

...

...

verified backup is probably good advice..

does resize2fs relocate blocks or is it restricted to shrinking only to last high water block in use ?

I found this in resize/resize2fs.c.unused_group_blocks

/*

• Resizing a filesystem consists of the following phases:

•  1.  Adjust superblock and write out new parts of the inode
  

•          table
  

•  2.  Determine blocks which need to be relocated, and copy the
  

•      contents of blocks from their old locations to the new ones.
  

•  3.  Scan the inode table, doing the following:
  

•          a.  If blocks have been moved, update the block
  

•                  pointers in the inodes and indirect blocks to
  

•                  point at the new block locations.
  

•          b.  If parts of the inode table need to be evacuated,
  

•                  copy inodes from their old locations to their
  

•                  new ones.
  

•          c.  If (b) needs to be done, note which blocks contain
  

•                  directory information, since we will need to
  

•                  update the directory information.
  

•  4.  Update the directory blocks with the new inode locations.
  

•  5.  Move the inode tables, if necessary.
  

*/

-- Kind Regards, Markus Falb

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