Service providers typically define quality of service problems using
threshold tests, such as ``Are HTTP operations greater than 12 per second
on server XYZ?" This paper explores the feasibility of predicting
violations of threshold tests. Such a capability would allow providers to
take corrective actions in advance of service disruptions. Our approach
estimates the probability of threshold violations for specific times in the future. We model the threshold metric (e.g., HTTP operations per second) at two levels: (1) nonstationary behavior (as is done in workload forecasting for capacity planning) and (2) stationary, time-serial dependencies.Using these models, we compute the probability of threshold violations.Our approach is assessed using simulation experiments and measurements of HTTP operations per second on a production web server. For both assessments, the probabilities of threshold violations produced by our approach lie well within two standard deviations of the measured fraction of threshold violations.
By: Joseph L. Hellerstein, Fan Zhang, Perwez Shahabuddin
Published in: RC21254 in 1998
LIMITED DISTRIBUTION NOTICE:
This Research Report is available. This report has been submitted for publication outside of IBM and will probably be copyrighted if accepted for publication. It has been issued as a Research Report for early dissemination of its contents. In view of the transfer of copyright to the outside publisher, its distribution outside of IBM prior to publication should be limited to peer communications and specific requests. After outside publication, requests should be filled only by reprints or legally obtained copies of the article (e.g., payment of royalties). I have read and understand this notice and am a member of the scientific community outside or inside of IBM seeking a single copy only.
Questions about this service can be mailed to reports@us.ibm.com .