Chimera - a new, fast, extensible and Grid enabled namespace service
Martin Gasthuber, Patrick Fuhrmann, Tigran Mkrtchyan · CERN Document Server (European Organization for Nuclear Research) · 2005
After successful implementation and deployment of the dCache system over the last years, one of the additional required services, the namespace service, has faced additional and completely new requirements.Most of them are caused by the scaling of the system, the integration with Grid services and the need for redundant (high availability) configurations.The existing system, having only NFSv2 access path, is easy to understand and is well accepted by the users.This single 'access path' limits data management task of making use of classical tools like 'find', 'ls' and others.This is intuitive for most users, but failed while dealing with millions of entries (files) and more sophisticated organisational schemes (metadata).The new system should support a native programmable interface (deeply coupled, yet fast), a 'classical' NFS path (now version 3 at least), a dCache native access and an SQL path allowing any type of metadata to be used in complex queries.Extensions with other 'access paths' will be possible.Based on the experience with the current system we highlight on the following requirements: * An animal from ancient Greek mythology with a lion's head and fore parts, a goat's body, a dragon's rear, and a tail in the form of a snake.