D4.2: Tier-0 and Tier-1 providers relationships

The HPC ecosystem can be classified by means of tiers, corresponding to levels of performance and operational policy and the defining characteristics and roles of tiers 0,1 and 2 are largely agreed. The development of this ecosystem and the promotion of Tier-0 usage is a formidable challenge both organisationally and technically. The delivery of the PRACE-2IP project beginning in Q3 2012 will expand the PRACE RI user community to include Tier-1 users, drawn from a large body of researchers already active at Tier-1. This reinforces the need for development of the ecosystem with respect to both the users and providers.
The PRACE AISBL is now very representative with 21 members. This broad membership has meant that the consultations undertaken in the course of its work by this task with most other Work Packages particularly 2, 3, 5 and 7 have resulted in contacts with the membership as a whole. The expansion of the HPC ecosystem in parallel with the progression of the PRACE Implementation Phase projects will bring with it new external relationships e.g. joint training with LinkSCEEM-2. The US TeraGrid programme has been identified as a potential partner in relationships that go beyond training. This task’s promotion of inter-tier migration to the HPC-Europa2 community addresses not only a wide geographical area but also a generally youthful demographic who will form part the HPC community in the future.
Together with Work Package 7 (Task 7.4.1) this task has participated in conducting an extensive user community survey and clearly established the potential for a well supported community to effect change in the codes they use due to their high level of involvement in code, demand for greater compute resources and understanding of the problem at hand. Greater availability of Tier-1 resources was identified as a key enabler of subsequent Tier-0 use, further validating a key aim of the PRACE-2IP project.
Case studies conducted by the task at the levels of a Tier-0 hosting country and two smaller countries with Tier-1 resources have provided insights into both ecosystem development and Tier-0 promotion. In each case dissemination and promotion of the opportunities offered by PRACE up to and including Tier-0 access is undertaken at national level. Assistance with the application process is readily available to researchers. Particularly in the case of the smaller nations the notion of the integration of Tier-0, and in time alternative Tier-1, access as part of a continuum of service available to their respective communities albeit with alternative access mechanisms is seen as crucial. Even in France, a Tier-0 hosting country, it is recognised that enablement work must be undertaken at the Tier-2 level if one is to foster a Tier-0 community to the extent that part of the response to Tier-0 provision has been to strengthen efforts at Tier-2 nationally.
Relationships that pertain to the ecosystem are key to its development. Within the PRACE project and RI relationships promote coordination of support, technical and organisational activity serving end users and service providers. The DEISA programme while not primarily concerned with inter-tier migration in effect faced the problem because of the performance differential that emerged between the systems involved, which were made up of a range of architectures. Consequently resource providers, scientific support staff and users developed a body of technical experience in this domain. The imperative to provide for a consistent experience for users across tiers and systems will primarily develop relationships between providers. PRACE has well developed plans underway for community involvement e.g. community code petascaling and a user forum. Recommendations have been made regarding the attributes of relevance to PRACE when considering an external relationship.
This task’s contact with the HPCWorld project has informed the guidelines it is developing which will in turn feed into future allocation processes through which users will access resources. Users too must recognise that Tier-0 represents not only a shift in what can be achieved relative to before but also a commensurate shift in competition and expectation. Thus there should be openness to approaches needed to building the best possible project that may not have been required in the context of Tier-1. Collaborations should be considered at least at European level and a strategic approach to ensuring that the necessary software requirements can be met within realistic time scales is important.