Unable to update Plesk: debconf: DbDriver “config”: /var/cache/debconf/config.dat is locked by another process

Symptoms

• Unable to update Plesk with the following error in /var/log/plesk/install/autoinstaller3.log:

  debconf: DbDriver "config": /var/cache/debconf/config.dat is locked by another process.

Cause

One or more files are being used by another running process and this blocks the Plesk update to complete correctly.

Resolution

1. Connect to the server via SSH;

   Note: if direct SSH access to the server is not possible, contact server administrator for further assistance.

2. Find the process ID that locks the file from the error message with:

   # lsof /var/cache/debconf/config.dat
   COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
   frontend 444515 root 4uW REG 252,0 60012 55592027 /var/cache/debconf/config.dat

3. Check the process via the following command:

   # ps auxf | grep 444515
   root 444515 0.0 0.0 60700 2196 pts/0 S+ Feb18 0:00 | _ /usr/bin/perl -w /usr/share/debconf/frontend /var/lib/dpkg/info/postfix.postinst configure 3.1.0-3ubuntu0.2

4. Kill the process.

   # kill -9 444515

5. Run the update process again.