Если кто-то тоже страдает от нерабочего System Event Log на некоторых моделях серверов после ребута vCenter (как минимум Intel S2600WF и IBM x3550 M4), то ждём исправления бага 2754138:
After rebooting vCenter, reviewing ESXI Hardware Health fails until restarting vpxa or disconnect/reconnect ESXI host. Error: "A general system error occured: Retrieve IPMI SEL request to host failed".
The issue happens here because after reboot the vCenter does not find any value for bios->MajorRelease.
I am trying to understand why this data was not updated for VC after restarting(unless host is re-connected or vpxa restarted). This issue will be fixed in the future releases.