This has nothing to do with WebSphere, but I recently had some local fan failures and did some research:
The maximum operating temperatures for an IDE or ATA spinning disk hard drive are 0 to +60°C (+32 to +140°F). Hard drives have internal temperature sensors (which computer programs can also read and report) and some may shut themselves off after hitting +65°C:
Warnings are issued when the temperature exceeds the customer set threshold (or the default value 60°C). While this threshold can be disabled by the customer, the shutdown threshold, set to 65°C, cannot. (http://wdc.com/wdproducts/library/other/2579-850122.pdf)
The maximum operating temperatures for a solid state hard drive are -25 to +85°C (-13 to 185°F): http://www.seagate.com/docs/pdf/whitepaper/tp585_ext_envir.pdf
Example of querying drive temperature on Linux (use fdisk -l to list drives): hddtemp /dev/sda1
Studies from Google on over 100,000 of its spinning disk hard drives only shows temperature to be a problem at extremes and at age. It seems to me that +30 to +40°C (+86 to +104°F) operating temperature is about the optimal range.
In this study we report on the failure characteristics of consumer-grade disk drives. To our knowledge, the study is unprecedented in that it uses a much larger population size than has been previously reported and presents a comprehensive analysis of the correlation between failures and several parameters that are believed to affect disk lifetime.
One of our key findings has been the lack of a consistent pattern of higher failure rates for higher temperature drives or for those drives at higher utilization levels. Such correlations have been repeatedly highlighted by previous studies, but we are unable to confirm them by observing our population...
Figure 4 shows the distribution of drives with average temperature in increments of one degree and the corresponding annualized failure rates. The figure shows that failures do not increase when the average temperature increases. In fact, there is a clear trend showing that lower temperatures are associated with higher failure rates. Only at very high temperatures is there a slight reversal of this trend.
Figure 5 looks at the average temperatures for different age groups. The distributions are in sync with Figure 4 showing a mostly flat failure rate at mid-range temperatures and a modest increase at the low end of the temperature distribution. What stands out are the 3 and 4- year old drives, where the trend for higher failures with higher temperature is much more constant and also more pronounced.
Overall our experiments can confirm previously reported temperature effects only for the high end of our temperature range and especially for older drives. In the lower and middle temperature ranges, higher temperatures are not associated with higher failure rates. This is a fairly surprising result, which could indicate that datacenter or server designers have more freedom than previously thought when setting operating temperatures for equipment that contains disk drives. We can conclude that at moderate temperature ranges it is likely that there are other effects which affect failure rates much more strongly than temperatures do.
Failure Trends in a Large Disk Drive Population, Google Inc, 5th USENIX Conference on File and Storage Technologies, February 2007, http://static.googleusercontent.com/external_content/untrusted_dlcp/research.google.com/en/us/archive/disk_failures.pdf.