When ever a browser has the summary page loaded, there is a tremendous amount of IO. What exactly is this IO to/from? With out taking a huge dive into it, I know it's outbound IO and it's mostly "other" type of requests, like opening files and updating file system meta data.
The Splunk file structure is NFS mounted. If I have too I could pull this data local to the OS with hopes the local file system caching could deal with these quests better on a normal file system.
No, I ran into that problem with the memory. This is a different problem. I think it's intended.
The solution should very well be to prevent normal users from accessing the summary page.
And this Splunk Answer might be the issue you having