The OktoberTest data was all processed twice, once using a single AFS volume for temporary storage, once using 2 volumes. Load balancing between the volumes was done by staging even chunks on one volume and odd chunks on the other. Crumb-level products were staged on the same volume as the chunk which contained them. The attached plot shows the time to deliver the various data products for all 15 orbits. Different symbols denote the different file types. The line is y=x. A fit to a line through the origin had a slope of 0.74. This underestimates the advantage of dual staging disks, as 2 of the dual-disk runs were delayed by a database failure.
Now staging outputs but not inputs, using a fixed number of variable-sized crumbs, and balancing crumbs across the 2 AFS staging volumes. Results for orbits 1 and 2 are compared to the 2-disk results (from the previous graph) below. 