I have seen an experimental linux box where

lvreduce -rL -10G /dev/main/repository  

worked without unmounting (i.e. even on root,home dir etc), but it does not on my server install

  • debian squeeze
  • LVM version: 2.02.111(2) (2014-09-01)
  • Library version: 1.02.90 (2014-09-01)
  • Driver version: 4.27.0
  • Linux kernel: 3.16.0-4-amd64
  • filesystem: ext3

what it the version combination which allows it?

PS: I tried to browse release notes of lvm but to no avail.


The command you issued will not reduce your LV, rather it will grow the LV by 10GB, concurrently expanding its filesystem.

Shrink/reduce a LV is a much more delicate operation, as you need to be absolutely sure that the filesystem inside the to-be-shrink volume does not overflow the new volume limit. For filesystems which do not support shrinking (eg: xfs), you can not resize the LV at all.

Anyway, what exact error/log do you have when executing your command?


ok, you are really speaking about growing the LV. On-line filesystem resize is a long-time supported features in pretty much any kernels. Can you post the log of your command? Please also add the output of pvs, vgs and lvs

  • Yes it is a mistake in the question, sorry. I made the correction. I also added information about filesystem used (ext3). Thanks. – gorn Feb 22 '16 at 15:41
  • It is asking whether it should umnount the system and when I say now it refuses to continue. If the exact workding is needed I can paste it here. – gorn Feb 22 '16 at 15:43

Versions you have should allow that.

I suspect the problem that you've done lvextend which extended the lvm volume but you have not extended your filesystem. So that there's a limited size filesystem lives on larger device now.

You should be able to resize your filesystem via resize2fs /dev/main/repository ( resize4fs /dev/main/repository, xfsgrow /dev/main/repository or something like that for other filesystems).

  • I am aware of the fact, that it can be done in two steps - resizind the fs first and than reducing the logical volume. But the question holds - can it be done on mounted drive. (I know it can, but under which versions). – gorn Feb 22 '16 at 15:44
  • As I said - your versions are definitely fine. It's been there for years and your system is relatively fresh. – rvs Feb 22 '16 at 17:22
  • I did not use lvextend, I am using lvreduce - it was mistake in the question, but I corrected that already. So it is mystery, because lvreduce just asks to unmount the disk giving no chance to go around it. I will update the question with the complete communication on terminal. – gorn Feb 24 '16 at 10:48

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.