Provisioning new LVM volumes?

Question

I looking to use LVM to easily limit a users usable disk space.

Is it possible to provision new LVM volumes from unallocated space LVM space without having to create/initialize all the drives and partitions again?

Lets say I have a volume group named "datag".

Can create new logical volumes as needed (lvcreate)? Or do I need to create them all at once?

I have been looking at this article but it doesn't really state if this is possible or not. http://www.linuxdevcenter.com/pub/a/linux/2006/04/27/managing-disk-space-with-lvm.html

Answer 1

If there is free space in the volumne group then you can create new logical volumes without affecting anything else.

If you leave free space, you can extend volumes, though you may not be able to do this without unmounted/remounting the filesystem, it depends on what filesystem you are using. You'll want to check the docs on the filesystem about how it supports filesystem changes.

If you are out of free space, you can at add more physical devices to the volume group without loosing anything also.

You also need to leave free space in the volume group if you want to take snapshots and so on.

The reference I usually refer to is the LVM Howto. In particular you probably should look at the section on common tasks.

Of course please don't assume that just because it all should work, you can ignore making backups of your data. Sometimes strange and bizarre things happen, and things that are supposed to work fail.