Re: [gentoo-user] About interpreting output of df -h

[Jake Moe]

On 12/03/10 08:24, Indexer wrote:
>
> On 03/12/2010, at 08:23, Harry Putnam wrote:
>
> > Can anyone tell me how determine what these kind of useless names
> > really mean?
>
> > From df -h
> > Filesystem            Size  Used Avail Use% Mounted on
> > rootfs                1.9G  283M  1.6G  15% /
> > /dev/root             1.9G  283M  1.6G  15% /
>
> > How are you supposed to tell what actual device these things are on.
>
> rootfs is a symlink to the device
>
> william@Xerxes / $ ls -al /dev/root
> lrwxrwxrwx 1 root root 4 Oct 31 18:26 /dev/root -> sda3
> william@Xerxes / $ df -h
> Filesystem            Size  Used Avail Use% Mounted on
> rootfs                829G  803G   27G  97% /
> /dev/root             829G  803G   27G  97% /
> rc-svcdir             1.0M  132K  892K  13% /lib64/rc/init.d
> udev                   10M  304K  9.8M   3% /dev
> shm                   3.0G   24K  3.0G   1% /dev/shm
> /dev/sdb2             250G  234G   17G  94% /mnt/larry.1
> /dev/sdb3             682G  614G   68G  91% /mnt/larry.2
> /dev/sda1              31M   26M  3.3M  89% /boot
> william@Xerxes / $
>
> for example, when using UUID devices, the same is true
>
> william@Xerxes / $ ls -al /dev/disk/by-uuid/
> total 0
> drwxr-xr-x 2 root root 160 Nov 27 10:35 .
> drwxr-xr-x 6 root root 120 Nov  5 00:10 ..
> lrwxrwxrwx 1 root root  10 Oct 31 18:26
> 42f0c22c-dde5-4fbb-9d79-158b14d1faf8 -> ../../sdb2
> lrwxrwxrwx 1 root root  10 Oct 31 18:26
> 7ca26cca-04aa-4fe7-8b1b-5d9b059648a0 -> ../../sda1
> lrwxrwxrwx 1 root root  10 Oct 31 18:26
> 8a444308-a234-4c97-bd91-6e4ead0c5273 -> ../../sda3
> lrwxrwxrwx 1 root root  10 Oct 31 18:26
> b5af92b2-0e55-4b08-9c7f-ff2124c53921 -> ../../sdb1
> lrwxrwxrwx 1 root root  10 Oct 31 18:26
> cc02ce4e-3761-4084-ba82-d78b0c2cb636 -> ../../sda2
> lrwxrwxrwx 1 root root  10 Oct 31 18:26
> edf30a91-be1a-47ce-9c4a-d6ad89f94ee9 -> ../../sdb3
> william@Xerxes / $
>
> They are all just symlinks that are generated by udev.
>
>
>
> > I know I can look in fstab... but that is something of a crap shoot
> > since it is user configured.
>
> So? It should not be touchable by human hands unless they have root.
> The only way this would change is if someone changed it, and you can
> easily track who with sudo and modification times etc.
>
>
> > So what commands will show real devices not makebelieve baloney, and
> > allow me to see the usage devices are put to?
>
> Next time ask nicely. What is so hard about saying "Im a bit lost, how
> do i find the device that this points to".
>
>
> > Why do we use these kind of names anyway?
>
> It allows for dynamic configurations of things, and some other voodoo
> that can be done. For example, you can if using UUID's move all your
> disks in their sata ports, and not affect your system's mounts because
> root will point at the device as listed in the UUID section.
>
>
> > fdisk yes,  but you can't tell what usage the devices are put to
> with that.
>
>
>
>
> William Brown
>
> pgp.mit.edu
>
>
>
Out of curiousity, why don't I have a "rootfs" entry?  I just have the
actual device name.  You guys seem to be assuming that having "rootfs"
in the list is a normal thing, but it's not in my list?

jmoe@aus8617 ~ $ df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda6              76G   59G   14G  82% /
udev                   10M  216K  9.8M   3% /dev
/dev/sda3              33M  2.9M   28M  10% /boot
/dev/sda1              78G   30G   49G  39% /mnt/winxp
shm                   1.5G     0  1.5G   0% /dev/shm
/dev/sda2              78G   60G   18G  78% /mnt/win7

Jake Moe