Due to the way that NFA stores its data in a 2 tier system, you may want to consider configuring your Linux installation with Ext4 file systems to avoid the 32k subdirectory limit of Ext3.
When reaching this limit in a Ext3 environment you will notice that newly added interfaces will not contain any data when looking at timeframes greater than 2 hours. Also trying to create a directory under /opt/CA/NFA/Netflow/datafiles/ReaperArchive15 will generate an error of "mkdir: cannot create directory: Too many links".