9th IEEE/ACM International Symposium on Cluster Computing and the Grid Supporting distributed visualization services for high performance science and engineering applications – A service provider perspective Lakshmi Sastry*, Ronald Fowler, Srikanth Nagella and Jonathan Churchill e-Science Centre, Science & Technology Facilities Council, Introduction activities, the outcomes, the status and some suggestions as to the way forward. The Science & Technology Facilities Council is home to international Facilities such as the ISIS Workshops and tutorials Neutron Spallation Source, Central Laser Facility and Diamond Light Source, the National The take up of advanced visualization Grid Service including national super techniques within STFC scientists and their computers, Tier1 data service for CERN particle colleagues from the wider academia is quite physics experiment, the British Atmospheric limited despite decades of holding seminars and data Centre and the British Oceanographic Data surgeries to create awareness of the state of the Centre at the Space Science and Technology art. Visualization events generally tend to department. Together these Facilities generate attract practitioners in the field and an several Terabytes of data per month which needs occasional application domain expert. This is a to be handled, catalogued and provided access serious issue limiting the more widespread use to. In addition, the scientists within STFC of advanced visualization tools. In order to departments also develop complex simulations address this deficit, more recently, we have and undertake data analysis for their own begun an escalation of such events by holding experiments. Facilities also have strong ongoing show and tell “Other Peoples Business” to collaborations with UK academic and introduce exemplars from specific domains and commercial users through their involvement then the tools behind the exemplars, advertising with Collaborative Computational Programme, these events exclusively to scientists of various generating very large simulation datasets. There fields. In addition we have also begun holding is thus the need to support high resolution data one day workshops focussed on a single analysis using distributed compute, data and technology theme aimed at specific application visualization resources. At the same time, these domains, with practitioners and users sharing requirements offer the computational and their knowledge and experience with the users, visualization scientists within STFC unique with significant amount of time set aside for opportunities to advocate the take up of extensive question and answer and discussion advanced visualization techniques and toolkits in sessions. Two workshops sponsored under the distributed high performance, high resolution vizNET banner are typical examples of these, hardware environment. It gives an opportunity one aimed primarily at computational fluid to understand the requirements and usefulness of dynamists and those studying mechanics of distributed visualization. Given this seemingly movement and the other at Particle Physicists. advantageous position, the STFC vizNET These were aimed at STFC scientists and user partners have been actively pursuing communities at STFC Daresbury Laboratory and visualization awareness activities and services at the Harwell Science & Innovation Campuses aimed at application holders of various scientific respectively. The first was on advanced disciplines. These activities include holding visualization tools and techniques for high workshops, hands-on tutorials, show case performance applications in science and demonstrations and the setting up of hardware engineering. The workshop focussed on current based visualization services with technical best practice from a number of related support. This report provides details of these subdomains, on the role of VizNET in support of application developers, and also future 978-0-7695-3622-4/09 $25.00 © 2009 IEEE 586 DOI 10.1109/CCGRID.2009.94 requirements for the visualization of data from already. In addition, the feedback and the large-scale simulations that generate datasets experience also demonstrated that these new heading towards 10s of TB. Presentations technologies and software are far from offering included exemplars, algorithms for parallel ease of use, installation, documentation for the visualization, rendering, high resolution displays layers of client packages that are required all and ways to combine these to achieve near real factors being formidable obstacles to take up. time data exploration for extremely large datasets. In the next Section, the hardware, the software and support environment of the National The second was on Visualization and Data Visualization Service associated with the Mining for very large datasets (> 100MB). The National Grid Service and the use that is being predominantly particle physics research made of by the initial set of new users. audience were introduced to state of the art visualization toolkits and techniques, hardware Experimental National Visualization Service and distributed visualization using commodity (ENVS) graphics clusters to support real time analysis of LHCb, ATLAS and CMS experimental datasets STFC is attempting to estimate the requirements from CERN. There exemplars focus was to for scalable visualization within the UK demonstrate data mining and parallel academic research community through coordinates based visualization by international collaborations with other networks such as the speakers. EPSRC funded e-Research South to set up and reach out to new groups. We have set up a A third strand of activity was to hold a series of dedicated commodity visualization cluster hands on two days tutorial on computational (eVis) as an Affiliate member of NGS and reach steering, introducing the users the use of gViz across to new users. and RealityGrid steering libraries. The users were introduced to the use of compute resources eVis is a 17 node, 64-bit commodity cluster with of the UK National Grid Service, digital dual processors on each node with Linux certificate based authorization and operating system. The cluster is built using authentication in using distributed resources as a commodity components and open source precursor to using computational steering for software stack. It comprises a 17Node/34 complex application. processor infiniband connected cluster, each node equipped with an NVIDIA FX4500 high The considerable effort spent in getting end graphics card. These nodes can work application scientists to attend the events have together to render very large images in real time generated a slightly better response than before using the Tungsten Graphics Chromium and a small set of users who have never explored software. The cluster provides multi user remote advanced visualization tools have now joined access to these resources in batch mode via the Experimental National Visualization Service globus or interactively via gsissh/virtualGL/X11 to explore what the technology can offer their stack. The cluster provides access to serial and scientific productivity. In the UK, this gives us parallel rendering software such as NAG Iris an idea of effort required to bring in new user Explorer, ParaView and VTK. groups into the visualization community. On the NGS Affiliation status was formally achieved on other hand, despite considerable publicity, free nd registration and offer of follow-on support as 22 January 2009. This requires that the system well as holding the computational steering passes the rigorous ‘Inca’ acceptance grid schools at STFC site and at Manchester testing suite for a week without error, which was University which are close or local to large pool achieved in September 2008. Affiliation also of computational scientists brought little requires an entry in the Grid Operations Centre dividend with participants being mainly new Database (GOCDB https://goc.gridops.org/) to members of the groups that used such software be maintained with planned downtimes etc and a contact on the NGS Helpdesk so that user 587 support queries can be formally tracked. In resolution tiled displays to visualize extremely addition the cluster is integrated into the large datasets in high resolution which is very eScience monitoring framework using useful for medical and engineering applications. GANGLIA software to monitor usage and NAGIOS for alerts. The service has its own web site and user registration page. Hardware maintenance was recently extended and software licenses updated, including the acquisition of NAG mathematical and statistical and data mining libraries. A custom ‘visbsub’ user scripts hides some of the complexities of visualization data port forwarding over the encrypted ssh/gsissh links from the cluster to the client PC. Figure 2 Overview of VGL Visualization software stack VirtualGL is an open source package which gives any UNIX or Linux remote display software the ability to run 3D applications with full hardware acceleration [Figure 2]. VirtualGL can also be used in conjunction with remote display software such as VNC to provide 3D Figure 1 Architectural overview of hardware accelerated rendering for OpenGL Chromium with DMX applications. VirtualGL is very useful in providing remote display to thin clients which lack 3D hardware acceleration. VirtualGL can Chromium and VirtualGL are the two software be used in two modes, namely, VGL Image packages that are used for this purpose. Transport and X11 Image Transport. In the VGL Chromium