Problem: vSphere ESXi 6.7 host not responding in vCenter.
Error in vmkernel log:
2019-06-08T11:02:03.118Z cpu2:2136226)MemSchedAdmit: 470: Admission failure in path: sioc/storageRM.2136226/uw.2136226
2019-06-08T11:02:03.118Z cpu2:2136226)MemSchedAdmit: 477: uw.2136226 (185844) extraMin/extraFromParent: 256/256, sioc (808) childEmin/eMinLimit: 14066/14080
2019-06-08T11:02:03.118Z cpu2:2136226)MemSchedAdmit: 470: Admission failure in path: sioc/storageRM.2136226/uw.2136226
2019-06-08T11:02:03.118Z cpu2:2136226)MemSchedAdmit: 477: uw.2136226 (185844) extraMin/extraFromParent: 33/33, sioc (808) childEmin/eMinLimit: 14066/14080
2019-06-08T11:02:03.118Z cpu2:2136226)MemSchedAdmit: 470: Admission failure in path: sioc/storageRM.2136226/uw.2136226
2019-06-08T11:02:03.118Z cpu2:2136226)MemSchedAdmit: 477: uw.2136226 (185844) extraMin/extraFromParent: 256/256, sioc (808) childEmin/eMinLimit: 14066/14080
2019-06-08T11:02:03.118Z cpu2:2136226)MemSchedAdmit: 470: Admission failure in path: sioc/storageRM.2136226/uw.2136226
The main Root Cause is SIOC running out of memory.
Resolution: N/A
Note: This known issue will be fixed in 6.7U3. which will may release in July/August 2019
Work Around:
Users can workaround the issue by restarting the SIOC service using the following commands on the affected ESXi Hosts:
1. Check the status of storageRM and sdrsInjector
/etc/init.d/storageRM status
/etc/init.d/sdrsInjector status
2. Stop the service
/etc/init.d/storageRM stop
/etc/init.d/sdrsInjector stop
3. Start the service
/etc/init.d/storageRM start
/etc/init.d/sdrsInjector start
If the issue persists even after the SIOC service is restarted, users can temporarily disable SIOC by turning off the feature from VMware Virtual Center.
Refer VMware KB VMware Knowledge Base