Access Server: "ERR_EMPTY_RESPONSE" When Uploading or Renewing Web SSL Certificates

Description: If you encounter the error, ERR_EMPTY_RESPONSE, when trying to upload or renew web SSL certificates via Admin Web UI on your Access Server, it's likely due to insufficient disk space.

You might see a message like this:

ateChild: [Errno 28] No space left on device: cws/cmain:93,internet/defer:1418,cws/cmain:227,conf/instgen:26,conf/dmggen:30,conf/genbase:36,python3.6/shutil:122,python3.6/shutil:82 (OSError)'

This indicates that the Linux server hosting your Access Server is running out of disk space or inodes.

Check disk space and inodes

1. Connect to the console and get root privileges.
2. Check available disk space:
   

   df -TH

   • In our example, after checking the Disk Utilization, we can see that there is no Free Space on the disk:
     
3. Check available inodes:
   

   df -Ti

   • Available free space but no free inodes can indicate many small files on the filesystem or many links.

If you find no free space or inodes, follow the steps below.

Resolution

1. Delete unnecessary packages and clean the package manager cache

For Ubuntu/Debian:

sudo su 
apt-get autoremove 
apt-get clean

For Red Hat

sudo su
yum autoremove
yum clean all

2. Clean up log file in /var/log

Often, the files in /var/log cause high disk utilization.

1. List the files in the /var/log directory by size:

   cd /var/log
   ls -lsh --sort=size

   The directory's contents are displayed in descending order, largest to smallest.
   Or run this command:

   cd /var/log
   du -sh * | sort -rh

   Any of the two above shows you the files consuming more disk space.
2. Identify large files and clean up logs if possible.

3. Check and manage the Access Server log database (log.db)

1. Navigate to the Access Server database directory and list files by size:

   cd /usr/local/openvpn_as/etc/db
   ls -lsh --sort=size

2. If log.db is large, you can reduce its size with one of these two options:
   • Option 1: Wipe and vacuum the database:

     sudo /usr/local/openvpn_as/scripts/logdba --wipe
     sqlite3 /usr/local/openvpn_as/etc/db/log.db 'VACUUM;'

   • Option 2: Rebuild the database manually:

     service openvpnas stop
     cd  /usr/local/openvpn_as/etc/db/
     mv log.db log.db.backup
     sqlite3 log.db.backup .dump | sqlite3 log.db
     rm log.db.backup
     service openvpnas start

Tip: The Access Server log database contains information such as how long a user was connected, which user, how much bandwidth was used, etc.

4. Increase your hard disk size:

If cleaning up isn't enough, increase the disk size. We recommend at least 16 GB of disk space. If your hard disk has 4 GB or 8 GB, increase it to 16 GB. Refer to our Access Server requirement guidance for more.

If you have additional questions, submit a ticket.