32 DS8800 Performance Monitoring and Tuning
SARC and AMP play complementary roles. SARC carefully divides the cache between the
RANDOM and the SEQ lists to maximize the overall hit ratio. AMP manages the contents of
the SEQ list to maximize the throughput obtained for the sequential workloads. SARC affects
cases that involve both random and sequential workloads. AMP helps any workload that has
a sequential read component, including pure sequential read workloads.
Intelligent Write Caching (IWC)
Another additional cache algorithm, the Intelligent Write Caching (IWC), is implemented in
the DS8000 series. IWC improves performance through better write-cache management and
a better destaging order of writes. This algorithm is a combination of CLOCK, ...