Recent PDL Papers

File Systems Unfit as Distributed Storage Backends: Lessons from 10 Years of Ceph Evolution

Abutalib Aghayev, Sage Weil, Michael Kuchnik, Mark Nelson, Gregory R. Ganger,
George Amvrosiadis
SOSP ’19, October 27–30, 2019, Huntsville, ON, Canada.

For a decade, the Ceph distributed file system followed the conventional wisdom of building its storage backend on top of local file systems. This is a preferred choice for most distributed file systems today because it allows them to benefit from the convenience and maturity of battle-tested code. Ceph’s experience, however, shows that this comes at a high price. First, developing a zero-overhead transaction mechanism is challenging. Second, metadata performance at the local level can significantly affect performance at the distributed level. Third, supporting emerging storage hardware is painstakingly slow. [...more]

Parity Models: Erasure-Coded Resilience for Prediction Serving Systems
Jack Kosaian, K. V. Rashmi, Shivaram Venkataraman
SOSP ’19, October 27–30, 2019, Huntsville, ON, Canada.

Machine learning models are becoming the primary workhorses for many applications. Services deploy models through prediction serving systems that take in queries and return predictions by performing inference on models. Prediction serving systems are commonly run on many machines in cluster settings, and thus are prone to slowdowns and failures that inflate tail latency. Erasure coding is a popular technique for achieving resource-efficient resilience to data unavailability in storage and communication systems. However, existing approaches for imparting erasure-coded resilience to distributed computation apply only to a severely limited class of functions, precluding their use for many serving workloads, such as neural network inference. [...more]

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