'storage-simulator' is a simulator which simulating the function of the storage system ,using the data got for LSST(Large Synoptic Survey Telescope) by clusfs ,it is fulfilled according to the simgrid ,most of the api is provided by simgrid ,and we use the trace replay function to fulfill our target.

The main goal of developing the utility is to using the data got from LSST to simulator the storage system ,changing the development file to see which parameter affects the performance of the storage system most and then we can optimize the storage system of LSST.

• Download and install simgrid as:http://simgrid.gforge.inria.fr/simgrid/3.12/doc/install.html
• Use configure.sh to produce configuration files(filename_deployment.xml,filename_action_trace.txt,storage_content.txt) with the command:./configure.sh filename.csv
• Compile the program with the command "make"
• When you want to run the program , use the command: ./extracttrace platform.xml deployment.xml action_trace.txt action(sleep)

example of the command:./extracttrace --log=replay.thres:verbose --cfg=surf/precision:1e-9 one_host_one_disk.xml lsst-demo-v10.1-ubuntu-v14.04-cluefs_deployment.xml lsst-demo-v10.1-ubuntu-v14.04-cluefs_action_trace.txt action

• platform.xml:In order to run any simulation, SimGrid must be provided with three things: something to run (i.e., your code), a description of the platform on which you want to simulate your application and lastly information about the deployment process.http://simgrid.gforge.inria.fr/simgrid/3.12/doc/platform.html

• deployment.xml:When using SimGrid, you basically need your user code, a platform description, and something allowing to map your (simulated) process on your (simulated) platform. This is what deployment file is all about.So deployment file just consists of saying which process runs where and which arguments it should take as input.http://simgrid.gforge.inria.fr/simgrid/3.12/doc/deployment.html

• action_trace.txt:It describes the actions that each process executes.It is needed when simgrid replay the trace. The format of this file is : pid,action,filepath,duration,openid(open,read,write,flush,release,creat,readdir),position(read,write),bytereq(read,write)

• storage_content.txt:It describes the initial state of the storage disk. The format of this file is:filepath,filesize This file is used in the platform.xml .

• action(sleep):It is a parameter to decide which action you want your simulator to do.

Now is on going with changing the configuration of the storage.xml such as the parameter of the disk ,to see the change of time and then draw it on the plot as a curve to describe the time changes with the change of the disk parameter.