c99df3c4_nce_Guide___Configuring_Apache__Description
[Directive] JkShmFile [Description] 
Shared memory file name. Used only on unix platforms. The shm file is used by balancer and status workers. This directive is only allowed once. It must be put into the global part of the configuration. The default value is logs/jk-runtime-status. It is highly recommended that the shm file be placed on a local drive and not an NFS share. The shared memory contains configuration and runtime information for load balancer workers and their members. It is need in order that all apache children share the same status information for load balancing members (OK, ERROR, ...), share the information about load taken by the individual workers, share the information for the parts of the configuration, which are changeable during runtime by status workers.
The Apache Tomcat Connector - Reference Guide - Configuring Apache
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