PCDedup: I/O-Activity Centric Deduplication for Improving the SSD Lifetime

When data deduplication is used for extending the SSD lifetime inside an SSD, one of the key performance factors is how to manage the fingerprint cache. Since the size of the fingerprint cache is limited, the fingerprint cache should be very selective in choosing which fingerprints should be stored in the cache. In this paper, we show that write program contexts, which are automatically extracted during run time, can accurately capture their future data duplicability. Based on this observation, we propose PCDedup for SSD-internal data deduplication. PCDedup automatically filters out undesirable fingerprints from the cache, thus improving the cache hit ratio. Our experimental results show that PCDedup can improve the SSD lifetime by up to 16.4% over the existing deduplication scheme while the fingerprint management overhead is lowered on average by 68.6%.