Server: Ubuntu server 18.04 64-bit Memory: 1.5 GB Swap: 1.5 GB Hard disk: 70 GB (80% used) ISPConfig version: 3.1.13 Recently my server has become unstable: individual services frequently restart, especially amavis, clamd, apache2 and PHP-FPM, and sometimes the whole server becomes unresponsive or reboots spontaneously. I have not made any major changes that might account for this, although I do update the packages regularly. The top line of the monit webpage now frequently shows CPU usages like this: 7.3%us, 7.1%sy, 75.2%wa If I understand this correctly, the very high wait percentage indicates a problem with disk I/O. I have also noticed frequent occurrences of the following message in the HTML5 Serial Console: A stop job is running for /dev/xvda2 (56s / no limit) xvda2 is the swap partition. As there is 'no limit' on the failing stop job (why?), the server has to be manually restarted. Do these symptoms imply a problem with the swap partition, as I suspect? How should I troubleshoot it? I'd be very grateful for any help.