4th EGEE User Forum/OGF 25 and OGF Europe's 2nd International Event

Extending SRM and SRB interoperation

3 Mar 2009, 16:50

5m

Foyer (Le Ciminiere, Catania, Sicily, Italy)

Poster Grid Services exploiting and extending gLite middleware Poster session

Speaker

Dr Jens Jensen (STFC-RAL)

Description

Previously we have presented the outcome of SRM and SRB interoperation (at the UF in Clermont-Ferrand) using gLite for file transfers. Building on this work, we now show how much (and how) this can be extended to cover the management of user metadata and tracking file replicas. While primarily focusing on SRM and SRB, we also take a look at iRODS (the successor to SRB) to evaluate whether the same tricks can be used to achieve interoperation.

Keywords

interoperation, standards, data management, data access, SRM, SRB, storage element, file metadata

Conclusions and Future Work

Interoperation between grids is important and we extend previous work on file transfers using gLite by comparing metadata management, in particular datasets and replicas. We also look at data access from the users and applications. Interoperation in these areas greatly extend the range of use cases that the interoperation activities can fulfill.
Future work will look at iRODS, the successor to SRB.

URL for further information

http://forge.gridforum.org/sf/wiki/do/viewPage/projects.gin/wiki/GINDataEGEEUserForum2009?_message=

Detailed analysis

In the Grid world, two distinct data management resources are used: Storage Elements providing SRM (Storage Resource Manager) interfaces, and the SRB (Storage Resource Broker) from SDSC. In Clermont-Ferrand we presented basic interoperation using gLite: file transfer from SRM to SRB and back. We now build on this work in several directions. The principal part of this work investigates metadata, both file metadata (what the grid knows about the file) and user metadata (what the user knows about the file). In particular we compare the approaches to datasets and replicas and discuss how interoperation can be achieved at this level (it turns out to be not quite as simple as the basic interoperation - even so, the aim is to achieve the goals with a minimum of effort, particularly development effort). We also extend the work by comparing local access protocols (from applications). Finally, we take a brief look at iRODS with a view to extending interoperation to iRODS.

Impact

SRM and SRB have so far been considered isolated "islands" in the grid world. Our early work, presented last year, sparked a lot of interest, and we expect more interest as grids increasingly collaborate and merge. Our current extensions to this work will further extend the impact of achieving interoperation by bringing in further realistic use cases: we look at not just how the grids can manage data but also how users and applications manage them. This work is part of a wider range of OGF GIN ("Grid Interoperability Now") activities and as such aims to build bridges between grids. Here we focus on data management, and the biggest impact is achieved between collaborating grids using SRM (e.g. gLite based grids) on one side and "data grids" using SRB on the other. We bring data and metadata use cases from "real" users to show that the work is relevant and needed.