Dominik Zyla wrote: > You have right. While you checking sensors from few machines, you can > see the trend. Gotta think about changing the way of temperature monitoring > here. Myself I wouldn't rely on internal equipment sensors to try to extrapolate ambient temperature from their readings. Most equipment will automatically spin their fans at faster RPMs as the temperature goes up which can give false indications of ambient temperature. I do monitor the temperature of network equipment, but also have dedicated sensors for ambient readings. Already saved us some pain once, opened up a new location in London last year and the ambient temperature at our rack in the data center was 85+ degrees F. The SLA requires temperature be from 64-78 degrees. Alarms were going off in Nagios. The facility claimed there was no issue, and opened up some more air vents, which didn't help. They still didn't believe us so they installed their own sensor in our rack. The next day the temperature dropped by ~10 degrees, I guess they believed their own sensor.. http://portal.aphroland.org/~aphro/rack-temperature.png People at my own company were questioning the accuracy of this sensor(there was only one, I prefer 2 but they are cheap bastards), but I was able to validate the increased temperature by comparing the internal temp of the switches and load balancers were significantly higher than other locations. Though even with the ambient temperature dropping by 10+ degrees, the temperature of the gear didn't move nearly as much. The crazy part was I checked the temperature probes at my former company(different/better data center) and the *exhaust* temperature of the servers was lower than the *input* temperature from this new data center. Exhaust temperature was around 78-80 degrees, several degrees below the 85+. It seems the facility in London further improved their cooling in recent weeks as average temperature is down from 78 to about 70-72 now, and is much more stable, prior to the change we were frequently spiking above 80 and averaging about 78. Also having ambient temperature sensors can be advantageous in the event you need to convince a facility they are running too hot(or out of SLA), as a tech guy myself(as you can probably see already) I am much less inclined to trust the results of internal equipment sensors than a standalone external sensor which can be put on the front of the rack. nate
