To resolve this issue, you must investigate the cause of the I/O error.
To find additional information regarding the I/O error, investigate the VMkernel logs.
In the sample log in the Symptoms section, you see entries similar to:
Apr 25 15:16:19 vmkernel: 0:01:18:04.119 cpu0:4100)ScsiDeviceIO: 1688: Command 0x28 to device "naa.600508e0000000001bb2016e9948700a" failed H:0x0 D:0x2 P:0x0 Valid sense data: 0x3 0x11 0x0.
In this case, the failure occurred because of a SCSI read failure (Command 0x28) on the device due to hardware error:
MEDIUM ERROR / UNRECOVERED READ ERROR