# StashCache: A Distributed Caching Federation for the Open Science Grid

## TL;DR

StashCache is a distributed caching system designed for the Open Science Grid, enabling opportunistic users to efficiently utilize nearby storage and improve data distribution with minimal management overhead.

## Contribution

It introduces a novel distributed caching federation architecture that simplifies data sharing for opportunistic users across multiple sites.

## Key findings

- StashCache has been successfully deployed across the US and Europe.
- Performance analysis shows improvements over traditional HTTP proxies.
- The system supports multiple components including data origins, redirectors, caches, and clients.

## Abstract

Data distribution for opportunistic users is challenging as they neither own the computing resources they are using or any nearby storage. Users are motivated to use opportunistic computing to expand their data processing capacity, but they require storage and fast networking to distribute data to that processing. Since it requires significant management overhead, it is rare for resource providers to allow opportunistic access to storage. Additionally, in order to use opportunistic storage at several distributed sites, users assume the responsibility to maintain their data. In this paper we present StashCache, a distributed caching federation that enables opportunistic users to utilize nearby opportunistic storage. StashCache is comprised of four components: data origins, redirectors, caches, and clients. StashCache has been deployed in the Open Science Grid for several years and has been used by many projects. Caches are deployed in geographically distributed locations across the U.S. and Europe. We will present the architecture of StashCache, as well as utilization information of the infrastructure. We will also present performance analysis comparing distributed HTTP Proxies vs StashCache.