Today I was troubleshooting a disconnected vSphere 4.1 u1 host in the vCenter cluster by a customer. After connecting ILO and troubleshooting the vmkernel log I saw some errors flooding:
WARNING: VFAT: 155: File_Ioctl
Feb 10 21:56:45 vmkernel: 2:03:12:35.935 cpu0:672979)WARNING: VFAT: NotSupported_File_Ioctl:155: File_Ioctl
Aug 15 16:30:59 vmkernel: 122:14:58:30.147 cpu7:45795719)WARNING: VFAT: 155: File_Ioctl
These messages are generated by the VMware ESXi BusyBox implementation during interactions with the host’s filesystems.
These messages are informational and can be safely ignored.
This issue is resolved in ESXi 4.1 Update 2.