I moved http_sessions from /tmp to /home/mike/httpsessions in Frontend because it was deleted with Frontend reboot .
chmod +x $FABAN_HOME/benchmarks/OlioDriver/bin/fileloader.sh (This step is very important otherwise all subfolders access of http_sessions will be as root and error will not solve)
chomd 777 /home/mike/httpsessions/http_sessions
Make sure use the /home/mike/httpsessions/http_sessions in "PHP sessions directory" filed in https://cs-web-client-x64:9980/ when running benchmark.
Deleted some files form Frontend in order to make some disk space( because we have snapshot of it, it is not possible to increase its disk space in vSphere. Maybe we should boot it from a live disk and increase its disk space)