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diff --git a/content/devops/lvm_shrink_resize_partition.rst b/content/devops/lvm_shrink_resize_partition.rst new file mode 100644 index 0000000..a3f9e3a --- /dev/null +++ b/content/devops/lvm_shrink_resize_partition.rst @@ -0,0 +1,114 @@ +Note to Self: LVM Shrink Resize HowTo +##################################### + +:date: 2014-10-05 12:00 +:slug: lvm-shrink-resize +:tags: lvm, debian-installer, partition, debian +:author: copyninja +:summary: Post is a note to self describing LVM shrink and resize of + partition + +Recently I had to reinstall a system at office with Debian Wheezy and +I thought I should use this opportunity to experiment with LVM. Yeah +I've not used LVM till date, even though I'm using Linux for more than +5 years now. I know many DD friends who use LVM with LUKS encryption +and I always wanted to experiment, but since my laptop is only thing +I've and its currently perfectly in shape I didn't dare to experiment +it there. This reinstall was golden opportunity for me to experiment +and learn something new. + +I used Wheezy CD ISO downloaded using *jigdo* for installation. Now I +will just go bit off topic and want to share the USB stick +preparation. I have to say this because I had not done installation +for quite a while now. Last I did was during Squeeze time so like +usual I blindly executed following command. + +.. code-block:: shell + + cat debian-wheezy.iso > /dev/sdb + +Surprisingly USB stick didn't boot! I was getting **Corrupt or missing +ISO.bin**. So next I tried using `dd` for preparing. + +.. code-block:: shell + + dd if=debian-wheezy.iso of=/dev/sdb + +Surprisingly this also didn't work and I get same error message as +above. This is when I went back to debian manual and looked for +installation step and there I found new way! + +.. code-block:: shell + + cp debian-wheezy.iso /dev/sdb + +Look at destination, its a device and voilą this worked! This is +something new I learnt and I'm surprised how easy it is now to prepare +USB stick. But I still didn't get why first 2 methods failed!. If you +guys know please do share. + +Now coming back to LVM. I used default LVM when disk partitioning was +asked, and I used guided partitioning method provided by +`debian-installer` and ended up with following layout + +.. code-block:: shell + + $ lvs + LV VG Attr LSize Pool Origin Data% Move Log Copy% Convert + home system-disk -wi-ao-- 62.34g + root system-disk -wi-ao-- 9.31g + swap_1 system-disk -wi-ao-- 2.64g + +So guided partitioning of `debian-installer` allocates 10G for root +and rest to home and swap. This is not a problem but when I started +installing required software, I could see root running out of space +quickly so I wanted to resize root and give it 10G more, for this I +need to reduce the home by 10G for which I need to first unmount the +home partition. Unmounting home from running system isn't possible so +I booted into recovery assuming I can unmount home there but I +couldn't. `lsof` didn't show any one using /home after searching a bit +I found `fuser` command and it looks like kernel is using /home which +is mounted by it. + +.. code-block:: shell + + $ fuser -vm /home + USER PID ACCESS COMMAND + /home: root kernel mount /home + +So it isn't possible to unmount /home in recovery mode also. Online +materials told me to use live-cd for doing this but I didn't have +patience to do that so I just went ahead commented /home mounting in +/etc/fstab and rebooted!. This time it worked and /home is not mounted +on recovery mode. Now comes the hard part resizing home, thanks to +`tldp.org <http://tldp.org/HOWTO/LVM-HOWTO/reducelv.html>`_ I coud do +this with following step + +.. code-block:: shell + + # e2fsck -f /dev/volume-name/home + # resize2fs /dev/volume-name/home 52G + # lvreduce -L-10G /dev/volume-name/home + +And now the next part live extending the root partition again thanks +to `tldp.org <http://tldp.org/HOWTO/LVM-HOWTO/extendlv.html>`_ +following command did it. + +.. code-block:: shell + + # lvextend -L+10G /dev/volume-name/root + # resize2fs /dev/volumne-name/root + +And now important part! **Uncomment /home line in /etc/fstab so it +will be mounted normally in next boot** and reboot! On login I can see +my partitions updated. + +.. code-block:: shell + + # lvs + LV VG Attr LSize Pool Origin Data% Move Log Copy% Convert + home system-disk -wi-ao-- 52.34g + root system-disk -wi-ao-- 19.31g + swap_1 system-disk -wi-ao-- 2.64g + +I've started liking LVM more now! :) |