NLANR cache hierarchy statistics,
visualization, and roi

8 feb 98

nlanr cache pi: Duane Wessels
wessels@nlanr.net
data analysis: Alex Rousskov
rousskov@nlanr.net

we have not inherited the Earth from our parents;
we have borrowed it from our children
-- World Conservation Strategy, Grand Canyon newspaper, july 90

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aggregate statistics

daily traffic per NLANR caches (bytes and documents)

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daily traffic NLANR supercache

11 NLANR caches, off and on: BO, CH, DC, IT, LJ, PA, PB, SD, SJ, SV, UC.

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cumulative traffic ( 1 webit = O(10TB) )

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savings (doc, byte hit ratios) over course of project

supercache daily savings

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absolute daily savings

cumulative savings

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cumulative supercache savings (almost 1 webit)

note superlinear growth of saving rate.

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hierarchy statistics

(more recently collected) hierarchy analysis

direct fetch, remote miss

local hits, remote hits

Note SJ cache has no remote hits and misses.

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per-type statistics

absolute traffic (BO, (PB's stats similar)

doc types of 5% or more of intensity or volume

images largest category
but which documents most cache-valuable?

relative contribution per traffic category

per-type savings (images well ahead)

cumulative per-type savings

executables in 2nd place,
but low hit ratio reduces their caching efficacy

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return on investment

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9 feb 98, alex/kc, info@caida.org.