A good set of specs according to our engineers could be: 1. No side vending of hot air from the case. The systems will be placed into 19" racks and there is no place for the air to go if it's blown into the side of the rack. Even if you take the sides off then you still will have racks placed next to each other. Airflow should be 100% front to back.
2. Along with that, there should be no "cheat holes" in the top, bottom or sides of the case. All "fresh" air should be drawn in from the front of the chassis. Again, the system will be racked in a 19" rack and there is no "fresh air" to be drawn in from the sides of the case (see 1 above) nor will the holes be open when nodes are stacked one on top of the other in a fully populated rack (32 nodes per rack). 3. There should be a mechanical separation between the hot and cold sections of the chassis to prevent the internal fans from sucking in hot air from the rear of the chassis. 4. The power supply *must* vent directly to the outside of the case and not inside the chassis. The power supply produces approximately 20% of the heat in the system. That hot air must be vented directly out of the chassis to prevent it from heating other components in the system. 5. The system should employ fan speed control. Running high speed fans at less than rated speed prolongs their life and reduces power usage for the platform as a whole. Fan speed should be controlled by either ambient temperature or preferably by CPU temperature. 6. The system must have a way of measuring fan speed and reporting a fan failure so that failed fans can be replaced quickly. Michael Will / SE Technical Lead / Penguin Computing -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Bill Broadley Sent: Thursday, April 27, 2006 2:55 PM To: beowulf@beowulf.org Subject: [Beowulf] Opteron cooling specifications? I'm writing a spec for future opteron cluster purchases. The issue of airflow came up. I've seen a surprising variety of configurations, some with a giant rotating cylinder (think paddle wheel), most with a variety of 40x28 or 40x56mm fans, or horizontal blowers. Anyone have a fan vendor they prefer? Ideally well known for making fans that last 3+ years when in use 24/7. A target node CFM for a dual socket dual core opteron? A target maximum CPU temp? I assume it's wise to stay well below the 70C or so thermal max on most of the dual core Opterons. Seems like there is a huge variation in the number of fans and total CFM from various chassis/node manufacturers. A single core single socket 1u opteron I got from sun has two 40mm x 56mm, and 4 * 40mm x 28mm fans. Not bad for a node starting at $750. Additionally some chassis designs form a fairly decent wall across the node for the fans to insure a good front to back airflow. Others seem to place fans willy nilly, I've even seen some that suck air sideways across the rear opteron. In any case, the nature of the campus purchasing process is that we can put in any specification, but can't buy from a single vendor, or award bids for better engineering. So basically lowest bid wins that meets the spec. Thus the need for a better spec. Any feedback appreciated. -- Bill Broadley Computational Science and Engineering UC Davis _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
