Enabling Object Storage via shims for Grid Middleware

TL;DR

This paper explores integrating modern object storage systems with grid middleware through shims and plugins, enabling direct access and evaluating the practical tradeoffs and deployment experiences.

Contribution

It introduces a method for interfacing object stores with grid tools via shims and reports on deployment experiences and performance evaluations.

Findings

Successful deployment of Xrootd-Ceph interfaces for direct object-store access.

Development of plugins for Ceph in GFAL2 to bridge grid and object storage.

Insights into tradeoffs and challenges in integrating object storage with grid middleware.

Abstract

The Object Store model has quickly become the basis of most commercially successful mass storage infrastructure, backing so-called "Cloud" storage such as Amazon S3, but also underlying the implementation of most parallel distributed storage systems. Many of the assumptions in Object Store design are similar, but not identical, to concepts in the design of Grid Storage Elements, although the requirement for "POSIX-like" filesystem structures on top of SEs makes the disjunction seem larger. As modern Object Stores provide many features that most Grid SEs do not (block level striping, parallel access, automatic file repair, etc.), it is of interest to see how easily we can provide interfaces to typical Object Stores via plugins and shims for Grid tools, and how well experiments can adapt their data models to them. We present evaluation of, and first-deployment experiences with, (for example) Xrootd-Ceph interfaces for direct object-store access, as part of an initiative within GridPP\cite{GridPP} hosted at RAL. Additionally, we discuss the tradeoffs and experience of developing plugins for the currently-popular {\it Ceph} parallel distributed filesystem for the GFAL2 access layer, at Glasgow.