import os,time

enough=False
while not enough:
    print "checking disk space"
    statvfs = os.statvfs('/var/tmp')
    free=statvfs.f_bavail*statvfs.f_frsize
    free/=1024**3
    if free>5:
        print "there is enough space left on /var/tmp ({0}Gb)".format(free)
        enough=True
    else:
        print "waiting for diskspace ({0}Gb)".format(free)
        time.sleep(5)