I was coding my site on Apache Server. Suddenly an error came and I got the warning

This computer has only 1.3 GB remaining.

I knew that this was because of the log file in /var/log/apache2/subins/error.log.

I opened the folder in root and the file size of the log was 17 GB. I deleted the error file. I went on to the root trash folder to delete the log file permanently. I deleted the files and info folder in the 'root trash' folder. So I had erased the root trash folder. But things got wrong. I still get the warning

This computer has only 1.3 GB remaining

I think I did the wrong way to empty root trash.

I used Disk Usage Analyzer to find the log file to permanently delete . But the software didn't showed the file. What happened to the folder I deleted in 'root trash'?

Here's the screenshot of Disk Usage Analyzer after the search.

UPDATE: Now my computer memory is 1 KB after I run the web page again in which the error showed.

Output of df -T -H:

Filesystem    Type     Size   Used  Avail Use% Mounted on

/dev/sda7     ext4      40G    38G    21k 100% /

none      devtmpfs     455M   291k   455M   1% /dev

none         tmpfs     460M   3.4M   456M   1% /dev/shm

none         tmpfs     460M   312k   459M   1% /var/run