Quality of Service Guarantees for Dynamic Scientific Workflows

Date: Friday, January 30, 2009

Time:10:00am - 11:30am

Location: Bldg. 50F, Room 1647

Speaker:

Lavanya Ramakrishnan

Department of Computer Science Indiana University

Abstract:

Large scale computations from various scientific endeavors such as

bioinformatics, weather and storm-surge modeling, are composed as a

sequence of dependent operations or workflows. These workflows typically

access shared data and run computations on high-performance, grid or

cloud systems and have deadline, budget and accuracy constraints.

Today's resource mechanisms and protocols provide standard access to job

submission and data transfer to manage workflow execution. However there

are limited mechanisms to allow users to specify constraints, coordinate

requirements with mechanisms available at the resource level and provide

the end-user with bounds on the Quality of Service (QoS) that can be

expected given the variability in distributed environments. In this

talk, I present the WORDS (Workflow Orchestrator for Distributed

Systems) architecture that facilitates the separation of concerns

between resource and application layers for effective workflow

orchestration to meet deadline constraints. In the context of this

architecture I will discuss a probabilistic QoS model that accounts for

uncertainties in resource procurement and failures. I also present a

Markov reward model for performability analysis to help evaluate the

effect of availability variations on performance and cost. I use the

proposed QoS model to implement and evaluate workflow orchestration for

deadline and budget sensitive weather prediction workflows.

Host of Seminar:

   Arie Shoshani