Here is rather not interestingly looking error message popping up when you don’t have Syslog configured properly on ESXi 5.x. I have seen few variations of this error but only have one screenshot at hand!
In a nutshell the cryptic message says that you have logs configured on non-persistent storage and they’ll not survive a reboot of the host. If we look closely at the exact location they’re indeed configured to point at ESXi scratch partition i.e.  /scratch/log:
There are at least three ways to get us out of trouble in this situation: