Monitoring Virtuoso Memory Consumption What Like any other process, Virtuoso consumes system resources, including memory. Here we describe one way to monitor the memory consumption of a Virtuoso server instance. Why monitor memory consumption? In a mission critical application, running 24/7, memory consumption should be fairly consistent when the server is in use. A server should not consume all system memory, which may result in it hanging or being terminated by the operating system. How to monitor Virtuoso's memory consumption On a Linux or other Unix-like system, you can use a script like this, which we've called memcheck-virtuoso.sh, which checks the memory consumption directly at the process level: #!/bin/bash # saved to /tmp/memcheck-virtuoso.sh pid=$(pidof virtuoso-t); log=/tmp/mem-trace-virtuoso.txt; echo $(printf "%s %s %s" $(date +%FT%R) $(cat /proc/${pid}/status |grep VmSize) ${pid}) | tee -a ${log} This script outputs 3 columns: date-timestamp VmSize: the actual memsize of the Virtuoso instance (from the cat -> grep for that process id) the process id (or PID) of the Virtuoso instance Here is a sample: $ cat /tmp/memcheck-virtuoso.txt 2014-11-14T17:22 VmSize: 15724332kB 3974 2014-11-14T17:46 VmSize: 15874064kB 3974 2014-11-14T17:55 VmSize: 15874064kB 3974 2014-11-14T18:52 VmSize: 15878076kB 3974 2014-11-14T18:52 VmSize: 15878076kB 3974 2014-11-14T22:29 VmSize: 15878076kB 3974 2014-11-14T22:30 VmSize: 15878076kB 3974 2014-11-14T22:56 VmSize: 15878076kB 3974 2014-11-14T22:56 VmSize: 15878076kB 3974 2014-11-14T23:33 VmSize: 15878076kB 3974 2014-11-14T23:33 VmSize: 15878076kB 3974 2014-11-14T23:52 VmSize: 15878076kB 3974 2014-11-14T23:53 VmSize: 15878076kB 3974 $ The script can be run manually as required. It can also be set up as a cron job to run at a specified internal, e.g., 4 hours in the sample below: $ crontab -l |grep mem 0 */4 * * * /tmp/memcheck-virtuoso.sh Also See Technical discussion about Measuring Memory Usage