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RPC Count: RPCs during recovery for 1 backup is almost exactly 5 * segment count ignoring RPCs for client tablet map refreshes (80 segments here so 400 RPCs).
MasterServer::recoverSegment Performance
rabinpoly was discovered to be far too slow to use as our checksum (it added 5-10 seconds to recovery time). The attached graph demonstrates the overheads of various checksum routines on a 640MB (80x8MB segment) invocation of recoverSegment as simulated in the RecoverSegmentBenchmark application.