Hard disk temperature should be below 50′ c
High speed hard disks, small and crowded chassis can cause very high temperatures. This means that the hard disk is not able to cool down. Disk performance and reliability significantly decrease as temperature increases and above 50 °C failure can occur any time. Disk manufacturers often limit the maximum operating temperature to 50 degree centigrade. However, it is recommended to keep your hard disks at lower temperature (approximately 35-40 °C is good) to increase their life time.