Computing Service Outages During Cooling System Upgrades
Scientific computing will experience service outages during the week of January 5th while crews from Facilities and Operations complete upgrades to the chilled water system that keeps SLAC servers in Building 50—and some employees—at operating temperatures. Servers supporting most SLAC experiments must be shut down to reduce the heat load while the main cooling system is taken offline January 5–12. If all goes well, service will be restored by January 13.
The team will make every effort to ensure that the project does not affect enterprise computing, including business systems and telephone, e-mail, Web, Internet, printing and most data servers, including SLAC home directories. Systems crucial to ongoing data collection for the Fermi Gamma-ray Space Telescope and operations of the Linac Coherent Light Source will also remain available. For a detailed list of systems that will be shut down, please see the Cooling Outage Web page. Although unlikely, unseasonably warm weather could overcome the temporary, air-cooling systems that will be in place. In that case, it may become necessary to shut down some enterprise servers to protect them from overheating. If that happens, a notice will be posted to the above Web page and to the comp-out mailing list. If weather reports in early January predict exceptionally warm weather the week of the 5th, the work may be postponed and an announcement will appear in SLAC Today.
The shut-down is necessary to allow Facilities to complete upgrades to the 40-year-old chilled water pipes connecting Buildings 50 and 137, among others, to the main chilled water header located at the Building 23 utilities service tunnel (Building 000). New, 10-inch chilled water pipes were already installed along the underground segments of the new chilled water circulation route, including sections along Loop Road near Buildings 40 and 50.
The scheduled outage will start on January 5 and will last up through January 12. Starting January 5 at 12:00 p.m., the chilled water will be drained from the old pipes, which will then be cut at building entry points, where the new pipes will be connected. Three separate mechanical subcontractor crews will be working at Buildings 000, 50 and 137 to speed the work along during the outage period.
The upgraded chilled water system will provide much-needed additional cooling capacity. This work has been several months in the planning and was moved back from earlier in the fall to minimize the impact on SLAC staff. Management in the key scientific experiments was consulted to plan the timing and identify crucial systems to be kept online. If you have any questions about the computing outage, please contact Len Moss or Randy Melen.
—Len Moss, Harry Shin and Hieu Dao