Preparing your primary mount and swap with fdisk
I have 4 big drives on a new machine, each can hold up to 2Tb of data, at first I thought I’d use the first drive for the OS and the other 3 for a RAID5 (software controlled)
Then after I had installed the operating system, I decided it was a big waste, and that I’d only need about 80gigs for the OS, and that I should use the 1920Gb (-swap,-other blocks) to be part of the RAID.
The first thing I needed to do was to resize the primary partition, but you can’t really do this while you’re using it. So I restarted with the Ubuntu CD in rescue mode, and jumped to the part where you setup the partition sizes. I told it I wanted to make the first partition smaller, I made it 80Gb, I accepted the rest of the options, and after a long while, it was finished creating the file systems, but it seems like it did a mess.
I restarted without the CD, crossed my fingers, and it did boot.
I did a:
sudo fdisk -l Device Boot Start End Blocks Id System /dev/sda1 * 63 156264254 78132096 83 Linux /dev/sda2 156264255 2930272064 1387003905 5 Extended /dev/sda5 2882334168 2930272064 23968948+ 82 Linux swap / Solaris /dev/sda6 156264381 2834380079 1339057849+ 83 Linux /dev/sda7 2834380143 2882334104 23976981 82 Linux swap / Solaris
and there were 6 partitions, some overlapping, but the primary looked right. I entered fdisk and deleted the 5 other partitions, and started a new.
Created a new partition (2) for Swap. Since the machine has 8GB of Ram, that’s the amount of Swap I used for it. After the partition was defined, I changed it’s type to type 82 (Linux Swap)
Then I created another partition (3), this one using the remaining space, and set it’s type to 83 (Linux)
I wrote the changes (w) and exited. It told me that the changes were written but the partitions would not be used until I rebooted, so I rebooted.
When I came back and did:
sudo fdisk -l
There they were:
Device Boot Start End Blocks Id System /dev/sda1 * 1 9727 78132096 83 Linux /dev/sda2 9728 10700 7812500+ 82 Linux swap / Solaris /dev/sda3 10700 182402 1379193956 83 Linux
But now there was a problem, when I checked for the memory available there was no swap
$ free
total used free shared buffers cached
Mem: 8183920 198524 7985396 0 6668 70284
-/+ buffers/cache: 121572 8062348
Swap: 0 0 0
So, first thing, I made sure the swap was specified on /etc/fstab for the next boot to include the swap
/dev/sda2 none swap sw 0 0
And then I had to make a file system for the swap
sudo mkswap /dev/sda2
Then, the “free” command did show the swap:
$ free
total used free shared buffers cached
Mem: 8183920 220420 7963500 0 7552 86880
-/+ buffers/cache: 125988 8057932
Swap: 7812492 0 7812492
In this case I didn’t have to make the file system for the primary partition because it was already made, I suppose the term “making the file system” is the equivalent of saying “formatting the drive with a specific filesystem”
However I had to do it for the remainder of the disk:
sudo mkfs.ext3 /dev/sda3
I’ll let you know if I find anything different from the tutorials on how to make RAID5.
New /etc/fstab format in Ubuntu
I while later, I updated the /etc/fstab to include the UUID of the swap partition on the fstab, instead of the device name.
To obtain this UUID I learned about the vol_id command
$ sudo vol_id /dev/sda2 ID_FS_USAGE=other ID_FS_TYPE=swap ID_FS_VERSION=2 ID_FS_UUID=b9b825c2-85dc-4def-bfd1-9071042452fa ID_FS_UUID_ENC=b9b825c2-85dc-4def-bfd1-9071042452fa ID_FS_LABEL= ID_FS_LABEL_ENC= ID_FS_LABEL_SAFE=
Now my /etc/fstab file looks like this:
# /etc/fstab: static file system information. # #proc /proc proc defaults 0 0 # /dev/sda1 UUID=13676a4b-b669-4a7a-9776-cb10c7b492b9 / ext3 relatime,errors=remount-ro 0 1 #/dev/sda2 UUID=b9b825c2-85dc-4def-bfd1-9071042452fa none swap sw 0 0 /dev/scd0 /media/cdrom0 udf,iso9660 user,noauto,exec,utf8 0 0
