  In this paper, we present a comprehensive analysis investigating the
reliability of SSD-based I/O caching architectures used in enterprise storage
systems under power failure and high-operating temperature. We explore variety
of SSDs from top vendors and investigate the cache reliability in mirrored
configuration. To this end, we first develop a physical fault injection and
failure detection platform and then investigate the impact of workload
dependent parameters on the reliability of I/O cache in the presence of two
common failure types in data centers, power outage and high temperature faults.
We implement an I/O cache scheme using an open-source I/O cache module in Linux
operating system. The experimental results obtained by conducting more than
twenty thousand of physical fault injections on the implemented I/O cache with
different write policies reveal that the failure rate of the I/O cache is
significantly affected by workload dependent parameters. Our results show that
unlike workload requests access pattern, the other workload dependent
parameters such as request size, Working Set Size (WSS), and sequence of the
accesses have considerable impact on the I/O cache failure rate. We observe a
significant growth in the failure rate in the workloads by decreasing the size
of the requests (by more than 14X). Furthermore, we observe that in addition to
writes, the read accesses to the I/O cache are subjected to failure in presence
of sudden power outage (the failure mainly occurs during promoting data to the
cache). In addition, we observe that I/O cache experiences no data failure upon
high temperature faults.
