File system bafflement

[Patrick Asselman]

On 2014-09-02 11:12, R Kimber wrote:
> I'm at a loss to understand what's going on on my system.  I keep 
> getting
> messages that the root filesystem is full.  Since the entire system 
> is
> contained in / I'm not clear what this means.  Does it just refer to 
> the
> top directory level, or does it include subdirectories apart from 
> those
> with their own partitions, or does it refer to the whole lot?
>
> The disk usage analyser also claims that /media contains 2.4 TB and 
> is is
> "96% full", but /media surely is only the mountpoint for other disks. 
> There
> are, inter alia, two 2TB disks mounted there. The disk usage analyzer 
> says
> they are 49.9% used, while df says they are 66% used.
>
> The system is also a bit slow, though there's plenty of swap space 
> available.
>
> Yesterday I cleared the apt cache, and the wastebin, and removed some
> kernels, and reduced / usage to about 84%, but today it's full again. 
> It's
> hard to see where the problem lies since I've not done anything that
> involves the / partition that I'm aware of.  Though I noticed that an
> external USB disk had disk errors, which e2fsck corrected (Free 
> blocks
> count wrong - maybe the disk is failing) - does this have anything to 
> do
> with it?
>
> All the following have their own separate partitions:
> /usr, /var, /tmp, /home, /usr/local
> and df reports that they are all less than 50% full
>
> The size of the root partition is 4GB, and the top level directories 
> that
> do not have their own partitions amount to just over 1GB
>
> My system has 4GB of memory and is running 14.04 (3.13.0-35-generic) 
> that
> was upgraded from 12.04LTS.  I'm using the mate desktop.
>
> I'd appreciate suggestions as to what the problem might be.
>
> - Richard.
> --
> Richard Kimber

No idea what the problem is.

The root filesystem is the partition mounted as root / including all 
subfolders but excluding any partitions mounted on it such as /media and 
in your case /usr /var etc. If you do a df the line with "Mounted on:" = 
"/" is the root filesystem.

Can you please give us the exact message that you receive?
And also the output of "df -m" and "du -x -m -s /*" ?

That way we can see how big your root filesystem is.
If it is quite small, it may be that old kernel versions filled your 
root filesystem. After removing, possibly another update was installed, 
once again filling up the space. We should be able to tell you more 
after you give us more details.

Best regards,
Patrick Asselman