BSC JITPrefetch Middleware

Code for an OpenStack Swift Just In Time Prefetch middleware.

Instalation

• Clone this repository (git clone https://github.com/marsqui/jitprefetch_middleware.git)

• Run sudo python setup.py install

• Alter your proxy-server.conf to have the jitprefetch middleware [filter:jitprefetch] section.

[filter:jitprefetch]
use = egg:jitprefetch#jitprefetch
probthreshold = 0.75
totalseconds = 65
chainsave = /tmp/chain.p
nthreads = 200
twolevels = False

Where probthreshold is the minimum probability for an object to be prefetched, totalseconds is the maximum time difference between objects in order to be considered consecutive, chainsave is the location to save the chain and nthreads is the number of threads in the prefetch downloader pool. twolevels equsl to False explores just the next level of the Markov chain, while equal to True explores the next two levels of it.

• Also it is necessary to add this filter to the pipeline variable in the same proxy-server.conf file. This filter must be added after keystoneauth filter and before slo, proxy-logging and proxy-server filters.