Whenever a Storage I/O error occurs that impacts the NSX Manager VM, NSX Manager is configured to throw a kernel panic, generating a trace that ends in the following:
"end Kernel panic - not syncing: EXT3-fs: panic from previous error:"
VMware NSX Data Center for vSphere
Identify possible storage issues on the ESI host where the NSX Manager VM resides from /var/log/vmkernel.log for messages like the following:
2015-10-15T14:46:47.157Z cpu8:32919)HBX: 598: Reading HB at 3596288 on vol 'DataStore2' failed: No connection
2015-10-16T03:41:47.165Z cpu48:32921)HBX: 598: Reading HB at 3596288 on vol 'DataStore2' failed: No connection
Restore the external storage connectivity that NSX Manager is dependent on, and then re-power the NSX Manager VM.