Suppose there are 3 or more clients of libvirt: 1)nova 2)bash virsh commands 3)user customized ELF 4)etc.... The env LIBVIRT_DEBUG and LIBVIRT_LOG_OUTPUTS affects all of these clients, thus, they will all accumulate the logs into *ONE* file set by LIBVIRT_LOG_OUTPUTS. eg: [2015-03-07 00:33:30]: 103674: info : virDomainShutdown:3242 : enter virDomainShutdown domainname=VMName [2015-03-07 00:33:41]: 103674: info : virDomainShutdown:3253 : domain VMName shutted down [2015-03-13 00:53:44]: 5073: info : libvirt version: 1.2.7 [2015-03-13 00:53:44]: 5034: info : libvirt version: 1.2.7 [2015-03-13 00:53:44]: 5073: error : virNetSocketReadWire:1475 : End of file while reading data: Input/output error note: 103674: bash virsh command 5037: nova if we don't know that 103674 is just a virsh command, and suspect that it's nova, time would be wasted to find out who's the criminal. The improved log would be: [2015-03-07 00:33:30]: virsh: 103674: info : virDomainShutdown:3242 : enter virDomainShutdown domainname=VMName [2015-03-07 00:33:41]: virsh: 103674: info : virDomainShutdown:3253 : domain VMName shutted down [2015-03-13 00:53:44]: nova: 5073: info : libvirt version: 1.2.7 [2015-03-13 00:53:44]: myProc1: 5034: info : libvirt version: 1.2.7 [2015-03-13 00:53:44]: nova: error : virNetSocketReadWire:1475 : End of file while reading data: Input/output error So, here's the qeustion: Is it neccssary to add a ProcessName field in the logging file? if so, I'd like to apply a patch for this. thank you in advance.