Saturday the 7th
IRC Question and Answer Session
topic: Partitioning - Part Two
date: 7th February 2009
time: start 1330 UTC end 1430 UTC
location: IRC - #ubuntu-classroom on freenode.net
Partitioning from a terminal
Session 2
- Command line partitioning
- fstab
- chmod and chown
Notes
We will be making use of a shared terminal please make sure that you are connected before the session begins - the shared session will be set up approximately 30 minutes prior to the start time 1330UTC.
It will be of some help if you visit this chmod page and practise changing permissions to see the read, write and execute permissions change.
If possible please look at the NTFS and FAT32 permissions section on this fstab wiki page.
- The expected output from the shared terminal is shown below prior to the 7th February, please try and look through this prior to the session start to orientate yourself.
logs
IRC Logs
[07:Feb]:13:31<forestpixie> Ok - then this is the fdisk/fstab/chmod and chown session [07:Feb]:13:31<forestpixie> This session Is moderated – this means that you won't be able to talk until you have been voiced, you can /msg PArtyBoi2 and he can voice you in turn [07:Feb]:13:31* forestpixie sets mode +m #ubuntu-classroom [07:Feb]:13:32<forestpixie> Right then, to the session proper - I intend to first work through using fdisk which is a command line partition tool and then to format our new partitions. [07:Feb]:13:32<forestpixie> We'll follow that with a question/answer session [07:Feb]:13:32<forestpixie> Then we will take a look at the fstab file, this file gives static information about partitions we wish to mount on boot [07:Feb]:13:33<forestpixie> We will be looking at our own fstab files in relation to the / and swap partitions and then write the lines needed to mount our new partitions ,once again following that we will have a Q&A session [07:Feb]:13:33<forestpixie> The final part of the session will look at the chmod and chown commands, chmod can be used to change permissions on files, chown can be used to change file ownership. [07:Feb]:13:35<forestpixie> Ok - fdisk first, a little bit more here then we can look at the virtual terminal [07:Feb]:13:36<forestpixie> I am going to create the following partitions , 2 primaries, 1 extended and a logical inside it. [07:Feb]:13:36<forestpixie> You start fdisk with root rights on the device you wish to work with [07:Feb]:13:36<forestpixie> sudo fdisk /dev/sxy – the number of the drive can be found by using fdisk -l – check the virtual terminal [07:Feb]:13:37<forestpixie> You can see that it has listed 2 drives - we are going to use /dev/sdb [07:Feb]:13:37<forestpixie> so we will start fdisk on that drive [07:Feb]:13:38<forestpixie> m will givce you all the commands you can use here [07:Feb]:13:38<forestpixie> To create a new drive use 'n' it then asks us what type of partition we want, I want the first partition to be a primary, so to create a primary we use 'p' [07:Feb]:13:39<forestpixie> Now we need to tell fdisk which partition we want to create, I want it to be number 1 [07:Feb]:13:39<forestpixie> I am going to use cylinders to set up the sizes of the partitions – we can see from the previous fdisk output that the whole drive is 652 cyclinders in size. I used the default setting for the first cylinder of this partition [07:Feb]:13:39<forestpixie> Now I need to specify where the partition ends, for the first partition I use 200 as I want the partition to be that many cylinders in size [07:Feb]:13:39<forestpixie> I could if I wanted create the partition using a number to give it a size, you use G for Gb, M for Mb or K for Kb [07:Feb]:13:40<forestpixie> Finally I need to tell fdisk to complete the operation and write the new partition table, to do this use w [07:Feb]:13:40<forestpixie> If I use fdisk -l it should now show me my new partition, [07:Feb]:13:41<forestpixie> Ok I will now proceed to create the remaining partitions. First 1 more primary and then the extended with it's associated logical, this time I will make all the new partitions and then write the table at the end [07:Feb]:13:42<forestpixie> Now that I have an extended that choice is no longer possible, so now we can only create primaries or logical as you will see, further once fdisk knows I wish to create a logical it will only allow me to create it within the extended partition [07:Feb]:13:44<forestpixie> Ok so we now have our partitions created - at the moment they are all needing filesystems, before we do that I'll stop and you can tell me if I was to slow or fast :) [07:Feb]:13:44* forestpixie sets mode -m #ubuntu-classroom [07:Feb]:13:45<forestpixie> if you have any questions - ask now [07:Feb]:13:45* forestpixie sets mode +m #ubuntu-classroom [07:Feb]:13:46<forestpixie> on to creating the filesystems then - so back and forth between here and the terminal [07:Feb]:13:46<forestpixie> We can use the mkfs, mkdosfs and mkntfs commands here to accomplish this , the syntax to use this command is similar for all 3 [07:Feb]:13:46<forestpixie> sudo mkfs -t filetype /dev/sdxy , So the commands we will need to run in our vt are [07:Feb]:13:48<forestpixie> Ok we now have our created our new partitions and formatted them. [07:Feb]:13:49<forestpixie> As ther are no questions I'll carry on with fstab [07:Feb]:13:50<forestpixie> If you run cat /etc/fstab in a normal terminal you will see this at the top [07:Feb]:13:50<forestpixie> <file system> <mount point> <type> <options> <dump> <pass> [07:Feb]:13:51<forestpixie> This is part of my fstab relating to my / partition [07:Feb]:13:51* forestpixie gives voice to PartyBoi2 [07:Feb]:13:51<forestpixie> UUID=9d44e64b-0c3f-4376-93f5-7e0a4bc9afac / ext3 relatime,errors=remount-ro 0 1 [07:Feb]:13:51<forestpixie> OK, so now lets have a look at the fstab line in some more detail and then finally we can look at creating a new line. [07:Feb]:13:52<forestpixie> The first part to the UUID, you can if you wish use the device name instead of UUID [07:Feb]:13:52<forestpixie> to do so I would replace it with /dev/sda2 this would make my fstab line read so [07:Feb]:13:52<forestpixie> /dev/sda2 / ext3 relatime,errors=remount-ro 0 1 [07:Feb]:13:52<forestpixie> The advantage of using the UUID lies in it not changing unless a change is made to the partition itself, creating, removing or resizing other partitions doesn't affect the UUID of unaffected partitions. [07:Feb]:13:52<forestpixie> The next part of the line - / tells the system where we want our partition to mount, this partition is my install so I want it mounting as root [07:Feb]:13:53<forestpixie> Following the mount point is the filesystem type - mine is ext3, if you have a default installation yours should be the same, if you have any ntfs drives mounting then that would read ntfs or maybe ntfs-3g [07:Feb]:13:53<forestpixie> After the filesystem, any options are indicated, here relatime is the first option followed by the errors=remount-ro option - this second option is the one which will cause the system to remount the partition as read only [07:Feb]:13:53<forestpixie> The next section is set as 0 - this is the dump option and relates to whether the filesystem is backed up by dump, 0, the default is no. [07:Feb]:13:54<forestpixie> Finally we have the pass section - this is set to 1 - this controls the order in which a filesystem is checked by fsck, a 1 means that the partition is checked first, a 0 would stop the check and a 2 would mean it was checked last. [07:Feb]:13:55<forestpixie> If there any latecomers can they /msg PartyBoi2 with questions please :) [07:Feb]:13:55<forestpixie> Before we can actually mount any new partitions, we need to have somewhere to mount it, the mountpoint, so we do that by making a folder. [07:Feb]:13:56<forestpixie> I tend to use /mnt for my mounts – if you want the partition to be visible on the desktop then create your folder in /media instead [07:Feb]:13:56<forestpixie> To do that we would use the mkdir command like so [07:Feb]:13:56<forestpixie> sudo mkdir /mnt/foldername [07:Feb]:13:56<forestpixie> So to allow our new partitions to mount correctly I need to create their mountpoints - one for each partition we have created [07:Feb]:13:56<forestpixie> which I need to do no win the shared terminal [07:Feb]:13:58<forestpixie> So now we have the new folders in /mnt to use. [07:Feb]:13:58* forestpixie sets mode -m #ubuntu-classroom [07:Feb]:13:58<forestpixie> db1 - you have a question? [07:Feb]:13:58* PartyBoi2 gives voice to d1b [07:Feb]:13:59<d1b> yes what happens if you rename a luks lvm volume -> will it continue to work if you use the uuid in /etc/fstab or do you need to update initrd ? [07:Feb]:14:00<forestpixie> I don't know the answer to that - I've never used them [07:Feb]:14:00<forestpixie> if anyone else does I think you should be able to talk until I set the mode again [07:Feb]:14:02<forestpixie> so we've made our folders in /mnt now we need ot add them to fstab [07:Feb]:14:02<forestpixie> We are going to be editing the file with a terminal based text editor - it's useful to know your way around at least one - if you ever need to edit a file from the recovery menu then I'm afraid that a GUI editor like gedit, kate or mousepad will be of no use. [07:Feb]:14:03<forestpixie> so first we give tell it which partition we are mounting [07:Feb]:14:03<forestpixie> which is /dev/sdb1 [07:Feb]:14:03<forestpixie> Next we have to tell it our new mountpoint [07:Feb]:14:04* PartyBoi2 removes voice from d1b [07:Feb]:14:04<forestpixie> /dev/sdb1 /mnt/ext3 [07:Feb]:14:04<forestpixie> Next comes the filetype [07:Feb]:14:04<forestpixie> /dev/sdb1 /mnt/ext3 ext3 [07:Feb]:14:04<forestpixie> Next come any options you wish to pass – I add user here [07:Feb]:14:05<forestpixie> Finally we come to the dump and pass options, use the default 0 for the dump and 2 for the pass option, it is suggested that you allow fsck to check the drive, but if you wished it not to then you would set the pass option to 0 - you can change the frequency that fsck checks a drive [07:Feb]:14:05<forestpixie> Now I shall add the lines for our other 2 partitions, the ntfs and fat32 [07:Feb]:14:06<forestpixie> So that is the data entered into fstab, you would now need to save the file [07:Feb]:14:06<forestpixie> I would now mount to check that the partitions have mounted without any problems [07:Feb]:14:06<forestpixie> Assuming that there is no output on the screen then the partition has mounted. You can check to see with a couple of commands, but df is a bit easier to scan [07:Feb]:14:07<forestpixie> ok - it's possible that there is a apparmor operating on the terminal - I've done this ocne earlier and it worked without issue [07:Feb]:14:09<forestpixie> ok - we have a small problem in the shared terminal :( [07:Feb]:14:09<forestpixie> we can stop for a while for any questions - we are unmoderated so I think you can talk [07:Feb]:14:10<forestpixie> If you have questions ? [07:Feb]:14:10<unutbu> could you cat /etc/fstab please? [07:Feb]:14:10<forestpixie> yep [07:Feb]:14:10<unutbu> There is a space before dev/sdb2 [07:Feb]:14:11<unutbu> huh, weird [07:Feb]:14:12<forestpixie> so there was - pasting from abiword doesn't work as well as openoffice :) [07:Feb]:14:12<forestpixie> the vm is running on jaunty, I think there were some issues when the vm was set up - but he's not about so I can't ask [07:Feb]:14:13<forestpixie> I ran this previously and the log from the session is on the wiki page [07:Feb]:14:13<unutbu> Maybe there is some invisible character that came with the pasting? [07:Feb]:14:14<forestpixie> possibly I can try doing ti long hand :) [07:Feb]:14:18<forestpixie> thanks you unutbu :) [07:Feb]:14:18<unutbu> cool [07:Feb]:14:19<forestpixie> ok then we can move on if there are no questions :) [07:Feb]:14:19<unutbu> Could you do sudo fdisk -l one more time? [07:Feb]:14:19<forestpixie> first we can look at chown - changing ownership of files or folders [07:Feb]:14:20<forestpixie> I think that is the problem we had from the beginning with the vm unutbu [07:Feb]:14:20<unutbu> ok [07:Feb]:14:21<forestpixie> I have no idea why it shows them all as linux - nor did bodhi [07:Feb]:14:21<unutbu> when you use fdisk, you can use a command to change the partition type [07:Feb]:14:21<unutbu> it is interesting that you can proceed without doing so [07:Feb]:14:22<unutbu> within fdisk the command is 't' [07:Feb]:14:22<forestpixie> to be honest I've only used it a few times in anger - and I rarely have anything to do with win filesystems anymore [07:Feb]:14:22<unutbu> you can still do it; even on a partition with a filesystem [07:Feb]:14:22<unutbu> :) lol [07:Feb]:14:23<forestpixie> I can have a look later if you want [07:Feb]:14:23<unutbu> ok [07:Feb]:14:23<forestpixie> Nearly finished now [07:Feb]:14:23<forestpixie> There are 4 different permutations available for the owner and group changes [07:Feb]:14:24<forestpixie> so we'll make a folder in our /etx3 partition and change the owner and group to see the changes [07:Feb]:14:25<forestpixie> so we can change the fodler with chown [07:Feb]:14:28<forestpixie> so chown can change the owner or group for a folder or file [07:Feb]:14:28<forestpixie> chmod will change the permissions for files or folders [07:Feb]:14:29<forestpixie> the command is used like [07:Feb]:14:29<forestpixie> chmod 000 /path/to/file [07:Feb]:14:29<forestpixie> the numbers are made from 4, 2 and 1 - giving a combination of read, write and execute [07:Feb]:14:30<forestpixie> ls -al will show the current permissions - the d simply denoting that it is a folder rather than a file [07:Feb]:14:31<forestpixie> at the moment the folder temp has 755 permissions fro group and others - owner has read,write and execute [07:Feb]:14:31<forestpixie> so in the shared session I can change them [07:Feb]:14:33<forestpixie> so once we know the chmod and chown commands we can change the owner and permissions of any file or folder [07:Feb]:14:33<forestpixie> ok - thanks for coming along - that's it for the time being
(note: will be posted after the event)
Shared Terminal Session transcript
Tuesday January 27, 2009 12:05 PM MST
12:05:38 up 12:54, 1 user, load average: 0.00, 0.00, 0.00
Peace be with you root
root@ufbt:fdisk -l
Disk /dev/sda: 6442 MB, 6442450944 bytes 255 heads, 63 sectors/track, 783 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Disk identifier: 0x0004ae6f Device Boot Start End Blocks Id System /dev/sda1 * 1 743 5968116 83 Linux /dev/sda2 744 783 321300 5 Extended /dev/sda5 744 783 321268+ 82 Linux swap / Solaris Disk /dev/sdb: 5368 MB, 5368709120 bytes 255 heads, 63 sectors/track, 652 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Disk identifier: 0x00000000 Disk /dev/sdb doesn't contain a valid partition table
root@ufbt:fdisk /dev/sdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0xdf8bc6fe.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
Command (m for help): m
Command action
a toggle a bootable flag
b edit bsd disklabel
c toggle the dos compatibility flag
d delete a partition
l list known partition types
m print this menu
n add a new partition
o create a new empty DOS partition table
p print the partition table
q quit without saving changes
s create a new empty Sun disklabel
t change a partition's system id
u change display/entry units
v verify the partition table
w write table to disk and exit
x extra functionality (experts only)
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-652, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-652, default 652): 200
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.root@ufbt:fdisk -l
Disk /dev/sda: 6442 MB, 6442450944 bytes 255 heads, 63 sectors/track, 783 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Disk identifier: 0x0004ae6f Device Boot Start End Blocks Id System /dev/sda1 * 1 743 5968116 83 Linux /dev/sda2 744 783 321300 5 Extended /dev/sda5 744 783 321268+ 82 Linux swap / Solaris Disk /dev/sdb: 5368 MB, 5368709120 bytes 255 heads, 63 sectors/track, 652 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Disk identifier: 0xdf8bc6fe Device Boot Start End Blocks Id System /dev/sdb1 1 200 1606468+ 83 Linux
root@ufbt:fdisk /dev/sdb
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 2
First cylinder (201-652, default 201):
Using default value 201
Last cylinder, +cylinders or +size{K,M,G} (201-652, default 652): 401
Command (m for help): n
Command action
e extended
p primary partition (1-4)
e
Partition number (1-4): 3
First cylinder (402-652, default 402):
Using default value 402
Last cylinder, +cylinders or +size{K,M,G} (402-652, default 652):
Using default value 652
Command (m for help): n
Command action
l logical (5 or over)
p primary partition (1-4)
l
First cylinder (402-652, default 402):
Using default value 402
Last cylinder, +cylinders or +size{K,M,G} (402-652, default 652):
Using default value 652
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.root@ufbt:fdisk -l
Disk /dev/sda: 6442 MB, 6442450944 bytes 255 heads, 63 sectors/track, 783 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Disk identifier: 0x0004ae6f Device Boot Start End Blocks Id System /dev/sda1 * 1 743 5968116 83 Linux /dev/sda2 744 783 321300 5 Extended /dev/sda5 744 783 321268+ 82 Linux swap / Solaris Disk /dev/sdb: 5368 MB, 5368709120 bytes 255 heads, 63 sectors/track, 652 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Disk identifier: 0xdf8bc6fe Device Boot Start End Blocks Id System /dev/sdb1 1 200 1606468+ 83 Linux /dev/sdb2 201 401 1614532+ 83 Linux /dev/sdb3 402 652 2016157+ 5 Extended /dev/sdb5 402 652 2016126 83 Linux
root@ufbt:mkfs -t ext3 /dev/sdb1
mke2fs 1.41.3 (12-Oct-2008)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
100464 inodes, 401617 blocks
20080 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=415236096
13 block groups
32768 blocks per group, 32768 fragments per group
7728 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912
Writing inode tables: 0/13 1/13 2/13 3/13 4/13 5/13 6/13 7/13 8/13 9/1310/1311/1312/13 done
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 23 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.root@ufbt:mkntfs -f /dev/sdb2
Cluster size has been automatically set to 4096 bytes. Creating NTFS volume structures. mkntfs completed successfully. Have a nice day.
root@ufbt:mkdosfs /dev/sdb5
mkdosfs 3.0.1 (23 Nov 2008)
root@ufbt:mkdir /mnt/ntfs /mnt/fat32 /mnt/ext3
root@ufbt:nano /etc/fstab
# # Use 'vol_id --uuid' to print the universally unique identifier for a # device; this may be used with UUID= as a more robust way to name devices # that works even if disks are added and removed. See fstab(5). # # <file system> <mount point> <type> <options> <dump> <pass> proc /proc proc defaults 0 0 # / was on /dev/sda1 during installation UUID=26ec2fb6-a3b8-4ed0-843f-8e66ca2a974d / ext4 relatime,errors=remount-ro 0 1 # none was on /dev/sda5 during installation UUID=d4d1875d-8c1e-469f-990f-7a2967659c1d none swap sw 0 0 /dev/scd0 /media/cdrom0 udf,iso9660 user,noauto,exec,utf8 0 0 ##New Drives /dev/sdb1 /mnt/ext3 ext3 user 0 2 /dev/sdb2 /mnt/ntfs ntfs-3g auto,users,uid=1001,gid=100,utf8,dmask=027,fmask=1 37 0 0 /dev/sdb5 /mnt/fat32 vfat auto,users,uid=1001,gid=100,utf8,dmask=027,fmask=1 37 0 0
root@ufbt:mount -a
root@ufbt:df -h
Filesystem Size Used Avail Use% Mounted on /dev/sda1 5.7G 2.4G 3.0G 45% / tmpfs 245M 0 245M 0% /lib/init/rw varrun 245M 96K 245M 1% /var/run varlock 245M 0 245M 0% /var/lock udev 245M 60K 245M 1% /dev tmpfs 245M 0 245M 0% /dev/shm lrm 245M 2.4M 243M 1% /lib/modules/2.6.28-4-generic/volatile /dev/sdb1 1.6G 35M 1.4G 3% /mnt/ext3 /dev/sdb2 1.6G 8.4M 1.6G 1% /mnt/ntfs /dev/sdb5 2.0G 4.0K 2.0G 1% /mnt/fat32
root@ufbt:mkdir /mnt/ext3/temp
root@ufbt:ls -al /mnt/ext3/temp/
total 8 drwxr-xr-x 2 root root 4096 2009-01-27 12:13 drwxr-xr-x 4 root root 4096 2009-01-27 12:13
root@ufbt:chown guru /mnt/ext3/temp/
root@ufbt:ls -al /mnt/ext3/temp/
total 8 drwxr-xr-x 2 guru root 4096 2009-01-27 12:13 drwxr-xr-x 4 root root 4096 2009-01-27 12:13
root@ufbt:chown guru:guru /mnt/ext3/temp/
root@ufbt:ls -al /mnt/ext3/temp/
total 8 drwxr-xr-x 2 guru guru 4096 2009-01-27 12:14 drwxr-xr-x 4 root root 4096 2009-01-27 12:13
root@ufbt:chown root.root /mnt/ext3/temp/
root@ufbt:ls -al /mnt/ext3/temp/
total 8 drwxr-xr-x 2 root root 4096 2009-01-27 12:14 drwxr-xr-x 4 root root 4096 2009-01-27 12:13
root@ufbt:chmod 664 /mnt/ext3/temp/
root@ufbt:ls -al /mnt/ext3/temp
total 8 drw-rw-r-- 2 root root 4096 2009-01-27 12:15 drwxr-xr-x 4 root root 4096 2009-01-27 12:13
root@ufbt:chmod 600 /mnt/ext3/temp/
root@ufbt:ls -al /mnt/ext3/temp/
total 8 drw------- 2 root root 4096 2009-01-27 12:16 drwxr-xr-x 4 root root 4096 2009-01-27 12:13