nsnaps is a benchmark that is used to provide performance data that relates the number of snapshots, N, taken versus 
the time needed to untar a kernel source tree and sync. It can be run on two different configurations: nvram and 
normal (without nvram) with a specified chunk size and block size. 

How nsnaps works:
	* Before running the specified configuration(s), nsnaps:
		- runs N tests using a raw device and records the timing of the untar and the sync

	* For each configuration specified, nsnaps:
		- does a mkfs on the specified tar device
		- mounts the tar device to a specified directory
		- copies the kernel source tree tar to the mounted tar device
		- umounts the tar device
		- sets up ddsnap
		- takes snapshot 0 (this is currently commented out)
		- creates a file system
		- begins to run N tests

	* During each test, nsnaps performs the following operations:
		- mounts the origin volume to a specified directory
		- mounts the tar device 
		- cats tarball to dev/null
		- times the untar
		- unmounts the tar device
		- times the sync
		- unmounts the origin volume
		- takes a new snapshot

How to run nsnaps:

1. CONFIGURE
	- Go into your  ~/zumastor/zumastor/test/nsnaps directory
	- Open up the configuration file, config.sh, and modify each of the variables according to your setup.
	  Please pay special attentions to the following variables. You need to config them according to your system setup.
		TAR_DEV=/dev/tar
		ORIG_DEV=/dev/origin
		SNAP_DEV=/dev/snap
		META_DEV=/dev/meta
		RAW_DEV=/dev/raw
	
	-  Edit the run_all_configurations function in nsnaps.sh to include the configurations
	   you would like to run. To set the number of tests (snapshots), modify the num_tests 
	   variable in the same function. 

	     For example:

		/* run 16 snapshots on normal (without nvram) with 4k chunks */
		local -r num_tests=16
		run_configuration "native:normal:4k" 4k "" "" $num_tests

		/* run 64 snapshots on nvram meta device $META_DEV with 64k chunks and a 4k block size */
		local -r num_tests=64
              	run_configuration "native:nvram:64k" 64k $META_DEV 4k $num_tests 

2. RUN
	- while in your ~/zumastor/zumastor/test/nsnaps directory run the nsnaps script
	
	  ./nsnaps.sh 
	

3. VIEW DATA
	- The nsnaps script will automatically generate files that organize the timing data and it will
	  create a plot of all the tests that were run
 
	- ~/zumastor/zumastor/test/nsnaps/Config0 contains the performance data of the raw device
	- ~/zumastor/zumastor/test/nsnaps/ConfigN contains the performance data of  the Nth configuration

	- Inside each ConfigN directory you will find the following files:

		runtestN - includes the time of the untar and sync for snapshot N

		umountN - includes the time of the umount for snapshot N

	- Inside ~/zumastor/zumastor/test/nsnaps, you fill find the following files:
		
		raw	    - lists a table of values for the real time, usr time, and sys time (untar + sync)
			      for each test on the raw device	
					
		native:*:*k - lists a table of values for the real time, usr time, and sys time (untar + sync) 
			      for each snapshot of a given configuration

 		all_tests.jpg - the graph of number of snapshots, N, taken versus the time needed to untar a 
			        kernel source tree and sync for all configurations (including raw)