sean finney on 10 Dec 2011 03:29:45 -0800

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Re: [PLUG] Lost gigabytes? More information

On Wed, Dec 07, 2011 at 03:58:43PM -0500, Adam Zion wrote:
> OK, this is odd. Given that a check of filesize for / yields 50 49.2
> GB, and I don't have any 49.2 GB partitions, I decided to see if I
> could find where, exactly, this partition lives. First, I found 2 GB
> worth of files and copied them to my /home/adam directory. No change
> in disk usage of /- clearly, home does not live on this 49.2 GB /
> partition.

This is because you're mixing up a few concepts here.  "/" is a 49.2 GB
*filesystem*, not partition.  A partition is just a slice of disk which
may or may not correspond to a filesystem.  In your case, you have one
really big LVM partition which showed up in your fdisk -l output..
This partition is then used as a physical volume that is part of one
really big LVM volume group (vg).  This volume group then contains a
small number of logical volumes (lv's), which correspond 1:1 to most of
the mounted filesystems and swap devices.

If you run just plain "mount" or "df" you will see all the
mounted filesystems, many of which will be provided by devices named
/dev/mapper/vgfoo-lvbar or maybe /dev/vgfoo/lvbar, depending on your

Since /home/adam is likely not a filesytem mount|grep adam won't show
you the directory... my guess is that /home *is* a separate filesystem
though, and that's where stuff is going.  In most cases (linux anyway)
you can use the df command directly on any file or directory, and it will
give you filesystem stats for the fs that contains the file (i.e. try
"df /home/adam").  There's other more portable ways to figure it out,
but none that I know of are one liners like that :)

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