Mux Health Failure messages with Guest Introspection installed – NSX 6.4.0 or above
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Mux Health Failure messages with Guest Introspection installed – NSX 6.4.0 or above


Article ID: 325089


Updated On:


VMware NSX Networking


  • When Mux is not able to get health stats timely due to host being busy working on VM operations like vMotion / power on and off / new VMs bring up, you might see the error on vsphere UI “Lost Communication with ESX module” as shown:


  • On the GI VM hosts, you might see error messages on syslog.log like: 

    2018-09-15T01:45:26Z EPSecMux[695598]: [ERROR] (EPSEC) [695608] popen failed for pidof NSX-Context-Engine. Errno: 28 (errno is not set on allocation failures). Strerror: No space left on device.

    2018-09-15T01:45:26Z EPSecMux[695598]: [ERROR] (EPSEC) [695608] Exception encountered while querying Context Engine status, EPSecPosixError@tid=695608: popen failed. errno: 28 (No space left on device)

    2018-09-15T01:45:13Z EPSecMux[695598]: [ERROR] (EPSEC) [695598] Attempted to recv 46 bytes from sd 72, errno = 12 (Cannot allocate memory)

    2018-09-15T01:45:13Z EPSecMux[695598]: [ERROR] (EPSEC) [695598] [1751854430] Error on guest socket: SocketError on sd 72, in recv: Cannot allocate memory (12)


    2018-09-15T01:44:49Z EPSecMux[488907]: [ERROR] (EPSEC) [488907] read_key Namespace database operation failed for key 421FBCC4-3265-28EE-A36D-C0C9CF1170A3: No namespace found

    Note: The preceding log excerpts are only examples. Date, time, and environmental variables may vary depending on your environment.


VMware NSX for vSphere 6.4.x


The issue is seen when the host is busy processing a lot of VM operations in operations like bulk vMotion or bulk VM power off/on operations.

These are benign messages and shouldn’t cause any AV functionality from GI perspective.


The above error message would resolve itself. 

However, if you see this too frequently and the error message on the User Interface does not resolve itself or if there is any AV functionality impact, contact VMware Support and reference this Knowledge Base article (58845) in the problem description of your support request. For more information, see How to File a Support Request.