"CATTL: a content-aware flash translation layer enhancing the lifespan 
of flash memory based solid state drives",


Feng Chen, Tian Luo, and Xiaodong Zhang 

Proceedings of 9th USENIX Conference on File and Storage Technologies  
(FAST'11), San Jose, California, February 15-17, 2011.

Abstract

Although Flash Memory based Solid State Drive (SSD)
exhibits high performance and low power consumption,
a critical concern is its limited lifespan along with the
associated reliability issues. In this paper, we propose to
build a Content-Aware Flash Translation Layer (CAFTL)
to enhance the endurance of SSDs at the device level.
With no need of any semantic information from the host,
CAFTL can effectively reduce write traffic to flash memory
by removing unnecessary duplicate writes and can
also substantially extend available free flash memory
space by coalescing redundant data in SSDs, which further
improves the efficiency of garbage collection and
wear-leveling. In order to retain high data access performance,
we have also designed a set of acceleration
techniques to reduce the runtime overhead and minimize
the performance impact caused by extra computational
cost. Our experimental results show that our solution
can effectively identify up to 86.2% of the duplicate
writes, which translates to a write traffic reduction of up
to 24.2% and extends the flash space by a factor of up
to 31.2%. Meanwhile, CAFTL only incurs a minimized
performance overhead by a factor of up to 0.5%.