Cisco Prime Network Analysis Module (NAM) 5.1

Question

Hi I have NAM-2 with software version 4.2 installed in my network and i am making very good use of these module for troublshooting,
I can run multiple captures files at local disk simultaneously and i can decode real time any capture file which is running.
I want to clarify following things,
I upgraded one of my NAM2 from 4.2 to 5.1 but i see following differences,
I cannnot do multiple captures at local disk simultaneously. it is not allowing me to create 2nd capture at localdisk while one is already running while in 4.2 version i can run multiple captures to local disk.
Its mean if i have 40G local disk, it's mean, it become reserved for one capture untill i stop and save there,
Also i cannot decode running capture file real time untill i stop.
I would apprecite if someone can clarify, whether it was enhancement in NAM 5.1?
Configuring Capture Sessions
You can create up to ten capture sessions, and only one capture session per disk (local or external).
http://www.cisco.com/en/US/docs/net_mgmt/network_analysis_module_software/5.0_1_T/user/guide/capting.html#wp1252570

Answer 1

NAM 5.x removes the ability to perform multiple captures to a single local disk because that results in unreliable capture behavior (packets may or may not be dropped depending on whether the disk can keep up with the data rate).
You should still be able to decode memory captures while running. For disk captures, the capture file must not be in use (i.e., for a multi-file capture, you can decode any file other than the one currently being written to).