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Summary: Deconstructing Commodity Storage Clusters
Haryadi S. Gunawi, Nitin Agrawal,
Andrea C. ArpaciDusseau, Remzi H. ArpaciDusseau, and Jiri Schindler #
Computer Sciences Department, # EMC Corporation
University of Wisconsin, Madison Hopkinton, Massachusetts
Abstract
The traditional approach for characterizing complex systems
is to run standard workloads and measure the resulting perfor
mance as seen by the end user. However, unique opportunities
exist when characterizing a system that is itself constructed from
standardized components: one can also look inside the system it
self by instrumenting each of the components. In this paper, we
show how intrabox instrumentation can help one understand the
behavior of a largescale storage cluster, the EMC Centera.
In our analysis, we leverage standard tools for tracing both the
disk and network traffic emanating from each node of the cluster.
By correlating this traffic with the running workload, we are able
to infer the structure of the software system (e.g., its write update
protocol) as well as its policies (e.g., how it performs caching,
replication, and loadbalancing). Further, by imposing variable
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