Verify stability of test runs with the big5 workload and its 1 TB data corpus

[gkamat]

Description

The big5 workload now features a 1 TB data corpus that can be optionally used. However, there are stability issues when the workload is run at high rates of ingestion and/or search.

This issue pertains to investigating this further and developing a strategy to resolve related problems and limitations.

[gkamat]

Workload has been tested at the 1 TB scale, and guidelines and caveats have been added to the README.