In this artice I’m going to show you how to expand your UFS filesystem under FreeBSD that runs in a Vmware Virtual Machine.
FreeBSD uses slices instead of traditional PC partitions. To sum it up shortly, it means that your whole disk contains only a single traditional partition with the partition type ‘freebsd(165)’. Inside this partition you will have slices. In a typical FreeBSD installation you have seperate slices for /, /usr, /var, /tmp and swap. In most cases the last slice on the partition is the /usr, and hopefully this is the one we have to extend, because in this case the only thing needed is to add some space to the end of the drive and extend the last slice. Sounds easy? Don’t think so!
The main steps are:
- Increase the actual (virtual) hdd size
- Extend the partition to cover the whole disk
- Extend the size of the last slice to cover the whole partition
- Extend the actual UFS filesystem on the newly modified slice
All the details:
First, forget livecds like gparted-live, knoppix, other partition hacking tools because they will not work.
- Stop your VM and Edit its settings
- Boot into single user mode (select 4 in the FreeBSD boot menu)
- check your new disk via dmesg, you will see the increased block number
but your partition is still at the previous size (fdisk -s)
- Let’s change the partition size using fdisk -u
In my example my partition starts at 63 and has the size of 18860247 blocks
What you would normally do is to adjust the new size to totalblocks-start. In this case fdisk will complain that the ending block is not on cylinder boundry. Fdisk will fix the value you entered but if you want to do the math yourself here is how it should be done correctly:
cylinder_size = 16065 [blocks]
new size = trunc(totalblocks/cylinder_size)*cylinder_size-startblock
in my case
trunc(25165824/16065)*16065-63 = 25157727
- Next step is to extend the slice size. Slices are edited with the bsdlabel utility. You might need to mount a couple of more partitions to access your editor.
EDITOR=<yourfav> bsdlabel -e
will bring up the slice table in your favorite editor. Now you need to change two things.
- First the line where it says do not edit: change it to your new partition size.
- To get the new size of the last slice you need to do the following calculations:
- The last step is to extend the FS itself on the new slice. Make sure you don’t have the slice in question mounted. Then run growfs /dev/
. In my case it was /dev/da0s1f
- To check your results run fsck, mount -a, df -h
- If you’re happy, you can reboot into multiuser mode now
Posted 2009/11/30 07:31 by jos