Magellan Final Report - Office of Science - U.S. Department of Energy

Magellan Final Report
comparison tools. MG-RAST is unique in its high-throughput analysis strategies, which have improved its
computational capacity by factor of 200 in the last two years. It uses a distributed load-balancing scheme to
spread the computationally expensive sequence similarity comparison across a large number of distributed
computation resources, including the Magellan systems. MG-RAST has been used to analyze 3 terabases of
metagenomic sequence data in the last six months.
The goal of the demonstration was to utilize the testbeds at both sites, and to explore potential failover
techniques within the cloud. The demonstration used 150 nodes from ALCF’s Magellan to perform the
primary computations over the course of a week, with NERSC’s Magellan acting as a failover cloud. Half
a dozen machines on ALCF’s Magellan were intentionally failed. Upon detecting the failures, the software
automatically started replacement machines on the NERSC Magellan, allowing the computation to continue
with only a slight interruption.
The same virtual machine image was used on both the ALCF and NERSC Magellan clouds. However,
this was not a simple port and required some changes to the image. The instance uses all eight cores on each
cloud node and about 40% of the available memory. The demonstration was a single run within the Deep
Soil project and represents only ˜1/30th of the work to be performed.
Use of the Magellan cloud allowed the project to dynamically utilize resources as appropriate, while
the project continued to work on algorithmic improvements. This demonstration showed the feasibility
of running a workflow across both the cloud sites, using one site as a failover resource. The project had
many challenges similar to STAR discussed above in terms of image management and application design and
development.
11.2.3 LIGO
Figure 11.5: A screenshot of the Einstein@Home screensaver Showing the celestial sphere (sky) with the
constellations. Superimposed on this are the gravity wave observatories (the three colored “angle images”)
and the search marker (a bulls-eye). Recent binary radio pulsar search work units also have a gray disc,
representing the radio receiver dish upon which the search is focused for that unit. (Image courtesy of
Einstein@Home.)
The Laser Interferometer Gravitational Wave Observatory (LIGO) collaboration is a dynamic group of
more than 800 scientists worldwide focused on the search for gravitational waves from the most violent
events in the universe. The collaboration developed the Einstein@Home program that uses donated idle
time on private personal computers to search for gravitational waves from spinning neutron stars (also called
pulsars) using data from the LIGO gravitational wave detector. Later, the LIGO researchers ported this
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