Partition resizing and Ubuntu

Hey all, it's been a while!

I have a question re: resizing partitions. I've only got less than 800MB free on my root partition. The new Ubuntu release is just around the corner, and I'm worried about running out of space during the update. Just want to run something by some of the local techies to make sure I'm doing things the right way.

1) I want to take a GB or two off of my /home partition and put it on my / partition so there's room for the update to take place and my Ubuntu to grow, which I am sure it will. I heard that you can't always do that, and that if you want to, things have to be setup in a very specific way (partitions have to exist in same logical volume or somesuch). here is some useful info (not sure if this is enough to be able to tell):

Code:

$ df -h Filesystem Size Used Avail Use% Mounted on /dev/sda1 5.6G 4.5G 795M 86% / varrun 2.0G 128K 2.0G 1% /var/run varlock 2.0G 0 2.0G 0% /var/lock udev 2.0G 52K 2.0G 1% /dev devshm 2.0G 12K 2.0G 1% /dev/shm lrm 2.0G 44M 1.9G 3% /lib/modules/2.6.24-19-generic/volatile /dev/sda3 171G 86G 77G 53% /home $ sudo fdisk -l /dev/sda Disk /dev/sda: 200.0 GB, 200049647616 bytes 255 heads, 63 sectors/track, 24321 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Disk identifier: 0x000e4c2b Device Boot Start End Blocks Id System /dev/sda1 * 1 730 5859375 83 Linux Partition 1 does not end on cylinder boundary. /dev/sda2 730 1692 7725585+ 83 Linux /dev/sda3 1692 24322 181776023 83 Linux

This is the default setup that my System76 laptop came with.

2) I am not dual-booting or anything like that. Pure Ubuntu. I keep reading online that if you're resizing a windows partition, you absolutely must defrag it before. Is that true of ext3 as well, or am I safe just going for it? Also, I am finding online that there is no real way to defrag ext3 filesystems (short of temporarily converting to ext2). I imagine it's sophisticated enough to make fragmentation a mostly negligible issue.

3) I burned a copy of PartedMagic to a boot CD, have booted with it, and ran gparted. It definitely lets me queue up the operations I am trying to perform (reduce my /home by 2GB, move the swap partition to the right, and increase my root partition to fill that bubble), but I haven't yet applied those changes. This is looking like good news, but who knows, maybe it'll complain about it. Or maybe it'll delete everything in the process hehe. Here's what I'm wanting to get it to do:

Code:

Current configuration: [ / 5.5GB ][ swap 7.0GB ][ /home 170GB ] New configuration: [ / 7.5GB ][ swap 7.0GB ][ /home 168GB ]

Erm... anyway, am I doing everything right here? I've backed everything up to an external HD, so I guess no biggie. Anything else I have to be aware of when performing this feat?

thanks!

I don't think Linux lets it's disk get fragmented. I think they use the same on-the-fly defragmentation that OSX does.

The reason that you should defragment before changing windows stuff around is because Windows defragmenter compacts everything to one end of the disk, this means what you are resizing is empty and it doesn't have to move anything. You don't have to do it, a good repartitioner should copy the files that it needs to, it just makes it faster.

I'm not sure how you backed up everything on your external, but I would make sure that you back up the files, not the file system. ie, just those files you need, don't make an image of the whole disk, that could cause problems.

Yup I just copied my home directory to the external HD, and backed up some key files from the root that I care about (sources.list, etc.) so no worries there :)

boot into a liveCD
ensure that neither your root or home partitions are mounted
fire up gparted (or qtparted, depending on desktop environment)
resize to suit

always a good idea to backup your system before hand

*edit*
to answer a few of the other queries

Quote:

Originally Posted by Replicon

I keep reading online that if you're resizing a windows partition, you absolutely must defrag it before. Is that true of ext3 as well, or am I safe just going for it? Also, I am finding online that there is no real way to defrag ext3 filesystems (short of temporarily converting to ext2). I imagine it's sophisticated enough to make fragmentation a mostly negligible issue.

There is actually no way of defragging an ext3 partition
you just can't do it

under normal use, ext3 does not fragment
ext3 does start fragmenting under special use cases
- after you exceed ~95% disk usage (but at this stage, a little fragmentation is the least of your worries - you have no space left)
- if you're writing large files (greater than 4Gb) that change constantly in size
(Eg. a time-shifting media centre, or a very high traffic database with lots of inserts)

Don't convert ext3 to ext2
you will lose a lot of meta-data attached to files
converting to ext2 should only be done when recovering data from a damaged disk

nice little explanation of fragmentation
http://geekblog.oneandoneis2.org/ind..._defragmenting

sweeet. I'll try it first thing in the morning!

Ack!

So I did it. It all looked like it worked out fine, but now, all I get is a GRUB flashing cursor. I imagine the resize might have moved the grub configuration out of the boot sector or something. I'll start googling, but if anyone knows the incantation to have this fixed, please post it :)

ah, this worked:

Code:

(from grub prompt) find /boot/grub/stage1 <<<said (hd0,0)>>> root (hd0,0) setup (hd0) quit

Hopefully it sticks :)

Note that "df -h" treats 1G as 2^30 (i.e. 1024^3) bytes, whereas fdisk treats 1GB as 10^9 (i.e. 1000^3) bytes. Likewise, "df -h" treats 1M as 2^20 bytes and fdisk treats 1MB as 10^6 bytes. I create my partitions with GNU parted using the "unit GiB" option, so that my numbers are consistent.