I have conducted an investigation into the default LCS file size. YCSB was used to perform all tests. The system under test consisted of a single rackspace node with 2GB of ram. YCSB workloada was used for all tests, which consists of 50/50 read/update workload with the total number of operations set to 900K. The amount of data was varied from 4GB to 40GB.
LCS file size was varied for the 4GB tests as 5MB, 10MB, 20MB, 160MB, 320MB, 475MB, 640MB, 1280MB. LCS file size for the 40GB tests was varied as 5MB, 40MB, 80MB, 160MB, 320MB, 640MB.
It is important to note that the 40GB test was not runnable with the current default LCS file size of 5MB due to consistent OOM errors. Those OOM issues go away with increased LCS file size.
Based upon the data from this experiment an LCS file size of 160MB would be an optimal default value. Please see attached graphs.