Calculating the size of /

[Colin Law]

On 11 September 2012 01:20, Jim Byrnes <jf_byrnes at comcast.net> wrote:
> On 09/10/2012 04:30 PM, PleegWat wrote:
>>
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>> On 09/10/2012 09:03 PM, Jim Byrnes wrote:
>>>
>>> In another thread I was trying to calculate how much disk space to
>>> allocate to / if I did a fresh install and this time setup  a
>>> separate /home partition.
>>>
>>> To get an idea of how much was outside of the home folder on my
>>> present install I did:
>>>
>>> sudo du -shc /  =>  105GB du -shc /home   =>  64GB
>>>
>>> This led me to believe I had 105GB - 64GB = 41GB that would be in
>>> /.
>>>
>>> Colin suggested I run Disk Usage Analyzer:
>>>
>>> Total filesystem capacity: 264.7GB(used: 104.5GB avail: 160.2GB
>>>
>>> /        100%        75.3GB home        84.1%        63.3GB usr
>>> 6.7%        5.0GB var        5.8%        4.4GB lib        2.1%
>>> 1.6GB opt        1.0%        762.2MB boot        0.3%
>>> 194.6MB
>>>
>>> Everything else was 0.0%
>>>
>>> So this seems to say that if I had a separate /home on this machine
>>> that / would be 12GB not the 41GB calculated above.
>>>
>>> So what accounts for the difference of 29.2GB between the used of
>>> 104.5GB and / of 75.3GB?
>>>
>>> The 12GB and 29.2GB = the 41GB I originally calculated would be
>>> needed for /.  12GB seems to be more in line with what others
>>> reported as the size needed for /.
>>>
>>> Regards,  Jim
>>>
>>>
>>
>> Hi,
>>
>> The 105 GB is probably correct, since it matches the total filesystem
>> usage reported by Disk Usage Analyzer
>>
>> The list returned by disk usage analyzer is probably off because of
>> data in directories your normal login user cannot read. This may
>> include data in root's home and trash, certain log directories, and
>> other users' data. Given that we're talking about 29GB, another user
>> account is the only thing that seems likely.
>>
>> Another user would have his own directory under /home. Other
>> directories containing data not readable by your user may be
>> discoverable running disk usage analyzer as root (Alt-F2, 'gksu baobab')
>>
>> You can also drill down using the --max-depth=1 option to du.
>>
>> PleegWat
>
>
>
> Your analysis appears to be correct.  I am the only user but the problem is
> in root's home and trash, as below:
>
> /                               100%                            42.9GB
> root                            67.5%                   28.9GB
>   .local                          99.8%                   28.9GB
>     share                       100.0%                  28.9GB
>       trash                       100.0%                          28.9GB
>         files                   100.0%                  28.9GB
>           backintime              99.9%                   28.9GB
>           <snip>
> .virtualbox/HardDisks   99.7%                   28.3GB
>
> I use backintime to do backups to an external usb drive. Back in April it
> was getting full so I used backintime to delete some backup sets. Somehow
> they seem to have ended up under root.
>
> I emptied the trash and reran the analysis.  Some of the numbers changed but
> the 28GB is still under root.  I even rebooted but it is still there.  How
> can I get rid of that 28GB?

Do you mean you still see it in the backintime folder under root?  If
so then you can use sudo with the command line to see what is in the
folder and remove it if appropriate, or you could run
gksu nautilus
in a terminal which will give you a nautilus window with root
permissions so you can do it graphically.  Be careful obviously and
make sure you do not delete something important when running as root.

Colin