sar - /var/log/sa/sa12: No such file or directory

Hello, i tried to install

yum install sysstat sar

and then do command: sar

It returns:
Cannot open /var/log/sa/sa12: No such file or directory


Someone adviced:
[QUOTE=dgbaker;70928]Manually create the sa direcotory with the owner as root. That should do it./QUOTE]


It appears not to work:
# sar
Cannot open /var/log/sa/sa12: No such file or directory
# mkdir /var/log/sa/sa12;chown root:root /var/log/sa/sa12
# sar
Invalid system activity file: /var/log/sa/sa12 (0)

Any ideas please?