Splunk will index an individual file, but will not index multiple files in the same directory as the original file

[carpga]

We had been updating an index with data from an individual file. However over the course of time this file grows large and slows down processes dependent upon the file to submit updates. So we modified our input to use the same directory where the initial file was located and create a daily file for indexing. Splunk appears to recognize the files exist, however is not indexing any of the data from files contained in the directory. These are csv files and we removed the header so each file would have a new unique name with new data in each file. However this does not appear to have remediated the issue as files are created. Again, Splunk can see the file count and is accurate, but no data is being indexed.

[n00badmin]

First thing is to determine whether Splunk is ignoring the file...

You can use the tailing processor url covered in this blog:

http://blogs.splunk.com/2011/01/02/did-i-miss-christmas-2/

Or I use the input stats in Splunk on Splunk

Or check your logs...

My first guess would be that you either need a longer initcrclength or crcsalt = source more on these here:
http://docs.splunk.com/Documentation/Splunk/6.2.0/Data/Howlogfilerotationishandled