New installation of Arch. EXT4?

JoeKer1086 · 2009-11-21 18:49:32

I installed Arch (and thoroughly read the wiki) and it failed at checking file systems. It said it could not locate the super block for /root. I used the by-label naming scheme and had a /boot, swap, /root and /home directory. /root and /home were both ext4, /boot was ext2. For some reason when checking file systems it could not locate the superblock on /dev/disk/by-label/root. When i tried to use the by-label to replace the superblock it could not be found so i had to use /dev/sda3 (which was /root) I tired several different superblocks (located with systemrescuecd-testdisk) with no success. I have formatted the drive and am going to try again but my question is "is there a problem using ext4 for /root and /home? i would really like to use ext4 but dont want to get through the installation again and have the same issue.

llcawthorne · 2009-11-21 19:35:59

I am running ext4 for my root and home fine. I am not doing anything by label though, except a couple of Win partitions. I am using LVM, so I have the /dev/mapper/[pv-lv] names in my fstab. Have you tried with UUID's?

JoeKer1086 · 2009-11-21 20:14:04

I will be honest....not a hundred percent sure how uuid works (and i read the wiki) how do i pick the uuid? is it just random hex code that i insert? it also seems kinda like a hassle.....

tavianator · 2009-11-21 20:29:15

UUIDs are unique identifiers assigned by the filesystem to each of your partitions. You can figure out which UUID is which partition by doing ls -l /dev/disk/by-uuid. But I agree with you, they are kind of a hassle, and labels are far more convenient. In answer to your question, there should be no problem with using ext4 for /root or /home. I doubt you'll get the same error again if you set everything up properly; if you do, post your partition table (fdisk -l) and /etc/fstab for us.

JoeKer1086 · 2009-11-21 21:21:51

Thanks guys, I will probably not have time until wednesday so if there is an issue i will post a new thread and post it in here (if you have time to follow up), thanks again

llcawthorne · 2009-11-22 04:03:45

Another easy way to get UUIDs of devices is to run `blkid`. Other than being longer to type, but otherwise not particularly different from working with labels. You just use UUID="<long string of hex here>". A line from blkid output is simply enough, looking like

/dev/mapper/array-archRoot: UUID="e64bec36-97cc-4983-a053-fa87dec3e0f4" TYPE="ext4" 
/dev/sdb1: UUID="F246925446921985" TYPE="ntfs"

And entries in fstab by mapper path, UUID, and label are like (from my fstab)

/dev/mapper/array-archRoot   /     ext4     defaults,noatime 0 1
UUID="F246925446921985" /mnt/windows    ntfs-3g users,uid=1000,gid=100,fmask=0113,dmask=0002 0 0
LABEL="Storage"         /mnt/winstorage ntfs-3g users,uid=1000,gid=100,fmask=0113,dmask=0002 0 0

I am sure you didn't need all that detail, but I like being thorough. Good luck! There's more help around if you see problems again.

JoeKer1086 · 2009-11-23 18:43:06

ok, i did a fresh install last night and got the exact same error....... i have a weird feeling i am not doing the whole by-label thing right so i am willing to do the by uuid but even after reading the wiki i really dont understand how to set up uuid.........i feel kinda dumb...im not sure where that long number comes from. The exact error i am getting is

/dev/disk/by-label/root: the superblock could not be read or does not describe a correct ext2 filesystem. If the device is valid and it really contains an ext2 filesystem (and not swap or ufs or something else), then the superblock is corrupt and you might want to try running e2fsck with an alternate superblock.

I have a feeling that it is because i set up by label wrong and it cant find it......if you can help me fix this i would appriciate it alot...i will post my fdisk -l and /etc/fstab when i am near that computer again.

milomouse · 2009-11-23 20:16:31

I use ext4 on my / and /home partitions and everything works fine. I've never had a problem with ext4. As far as using UUID's, which is what I use in certain cases, the previous advice is what I would suggest. If you're just looking for UUID's for what your mounted Linux partitions then I would also consider doing the following:

Note: I'm on my brother's laptop right now (running Linux Mint) but the same principle applies.

When I set up my fstab using UUID's I simply do the following:

$ ls -l /dev/disk/by-uuid/
total 0
lrwxrwxrwx 1 root root 10 Nov 23 14:52 4e6c48cd-eff1-44b3-ad3a-6968f2b443fe -> ../../sda5
lrwxrwxrwx 1 root root 10 Nov 23 14:52 506c706a-b6f3-4a43-a405-7c0ddfbe8f84 -> ../../sda1

So for sda1..

$ cat /etc/mtab | grep -i sda1
/dev/sda1 / ext3 rw,relatime,errors=remount-ro 0 0

(you can also use cfdisk or fdisk) From there I can deduct that /dev/sda1 is mounted on / (the root partition) and is UUID 506c706a-b6f3-4a43-a405-7c0ddfbe8f84 , so in /etc/fstab I'll add:

# /dev/sda1 entry in /etc/fstab file.
UUID=506c706a-b6f3-4a43-a405-7c0ddfbe8f84   /  ext3    relatime,errors=remount-ro   0 1

Again, I'm using on my brother's laptop right now so this is what his shows, as it's different than my Arch ext4 options. You can do this with each of your partitions and add them to the /etc/fstab file. I'm about to get on my laptop again so I can better examine the files. There's probably an easier way, like "llcawthorne" stated before;

With his way, using BLKID, you can view all your partitions at once. You can find your UUID for each partition and add them to your /etc/fstab like I mentioned earlier. UUID's really aren't that bad once you get to know which one belongs to what partition.

Last edited by milomouse (2009-11-23 20:18:45)

JoeKer1086 · 2009-11-23 20:29:07

thanks milomouse, that makes sense i will give it a try.....i am thinking the problem is due to the by-label....... because when i look at the boot options it is trying to find the kernal based on the root by uuid not by-label......i am new to arch so I knew I would have some problems but i thought by-label was something i understood....

Arch Linux

#1 2009-11-21 18:49:32

New installation of Arch. EXT4?

#2 2009-11-21 19:35:59

Re: New installation of Arch. EXT4?

#3 2009-11-21 20:14:04

Re: New installation of Arch. EXT4?

#4 2009-11-21 20:29:15

Re: New installation of Arch. EXT4?

#5 2009-11-21 21:21:51

Re: New installation of Arch. EXT4?

#6 2009-11-22 04:03:45

Re: New installation of Arch. EXT4?

#7 2009-11-23 18:43:06

Re: New installation of Arch. EXT4?

#8 2009-11-23 20:16:31

Re: New installation of Arch. EXT4?

#9 2009-11-23 20:29:07

Re: New installation of Arch. EXT4?

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