Isilon can be used for Splunk Cold or Frozen tiers only. Do not use Isilon for Hot/Warm. If you use the right Isilon Model (X410 or H500) then you will get performance that is aligned to Splunk benchmarks for a Cold or Frozen tier. Isilon has been validated by Splunk to meet or exceed performance benchmarks as it relates to Cold/Frozen. Hope this helps!