Basic Info
1)Experiment ran on trace taken from http://iotta.snia.org/tracetypes/3
2)The above site has hourly traces of 6 disks for 8 days.
3)We used the trace from 1200 to 1300 on 16/02/2016
4)I used only 1 hour trace(an the failure happens at the 40 minute mark) for the experiment because the hr ratio rises and saturates very quickly. 

Results
1)The relevant plots are included in the plots directory with the following nameing convention
<prewarm-set-size>-<prewarm-rate>-<heuristic>-<info>
where info can be
hr-5 -> shows the hit ratio during the 5 minutes after failure in the 3 cases(with pre-warming, without pre-warming, no failure)
hr-10 -> shows the hit ratio during the 10 minutes after failure in the 3 cases
hr-15 -> shows the hit ratio during the 15 minutes after failure in the 3 cases
hr -> shows the hit ratio for the entire 1 hour duration in the 3 cases
vdisk-hr5-wop -> shows the hit ratio(without pre-warming) for each vdisk during the 5 minutes after failure
vdisk-hr5-wp -> shows the hit ratio(with pre-warming) for each vdisk during the 5 minutes after failure
vdisk-hr -> shows the hit ratio(with pre-warming) for each vdisk during entire 1 hour duration

Key observations
1)Hit ratio, 5 minutes after failure is 0.85 without pre-warming and 0.87 with pre-warming
2)Pre-warming doesnt seem to help much here. This maybe because IOPS(around 700-800) of the disks are very high and the hit ratio is recovered very quickly
after failure.


Other Prewarming policies
1)I tried inserting the pre-wramed objects at the front of the LRU queue. The intution was that the important would be pushed
to the back of the queue by the time prewarming is done. But the results are with this strategy is worse than with the normal policy
