sysstat: Invalid system activity file: /var/log/sa/sa??

If you’re not able to run sar command of sysstat package use the following fix:

Move the invalid file and run
/usr/lib/sa/sa1
which should recreate the file.

Or you should be able to get this fixed once you try reinstalling sysstat package.

If you continue facing the issue, find out the sar binaries using which

# whereis sar
sar: /usr/bin/sar /usr/local/bin/sar /usr/share/man/man1/sar.1.gz

now check the time stamps on both the files

# ls -al /usr/bin/sar
-rwxr-xr-x  1 root root 56872 Jul 26 02:36 /usr/bin/sar

# ls -al /usr/local/bin/sar
-rwxr-xr-x  1 root root 47952 Aug  6 21:22 /usr/local/bin/sar

Remove the old on and link the new file. Now run the sar command to  see it working.

[root@server]# sar

Linux 2.6.xx-xx.x.x.elx.xxxstabxxx.xPAE (server.domain.info)     11/19/08

00:00:01          CPU     %user     %nice   %system   %iowait     %idle
00:10:01          all      2.03      0.00      0.49      2.10     95.38
00:20:01          all      0.40      0.01      0.11      0.03     99.46