[Note - this paper relies heavily on graphs, so the text version
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   Heuristic Cleaning Algorithms in Log-Structured File Systems
 
         Trevor Blackwell, Jeffrey Harris, Margo Seltzer
                       Harvard University
 
Abstract
 
Research results show that while Log-Structured File Systems (LFS)
offer the potential for dramatically improved file system performance,
the cleaner can seriously degrade performance, by as much as 40% in
transaction processing workloads [9]. Our goal is to examine trace
data from live file systems and use those to derive simple heuristics
that will permit the cleaner to run without interfering with normal
file access. Our results show that trivial heuristics perform very
well, allowing 97% of all cleaning on the most heavily loaded system
we studied to be done in the background.


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