TTB (Time to backup) : time needed to complete the backup. The number of uploaded fragments x+s respect the successful backup condition
TTR (Time to restore) : time needed to dowload the sufficient amount of fragment to reconstruct the original object
Cost : the amount of resources stored on the storage server
DC, PA-O, PA-P, P2P: respectively centralized, peer-assisted optimistic, pessimistic and Peer to peer approaches.
TTB distribution
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Storage cost in time
Finally, TTB is really low for PA-P, but it costs more.
Performances compare to Client-Server approach, with much lower costs.
PA and DC are not affected by peer death. P2P is. Close to DC approach without P2P problems
TTB in the different availability classes
Uneven distribution :
storage load in the different availability classes
TTB repartition and storage costs of selections
(optimistic approach and random selection)
=> highly scalable, storage server prevents Bootstrap
Heterogeneity in peers' capacity is compensated by the server