After a recent upgrade (not sure which) the sar command stopped working, with the error output:
Invalid system activity file: /var/log/sysstat/sa19
The saXX can be any number, and relates to the log file – which for some reason is corrupt/missing/unreadable. In my case it seems to exist, but doesn’t function.
I’ve found the best remedy to this to be purging sysstat from the system and reinstalling it, fairly trivial to script for multiple machines and seems to have fixed it up just fine.
Here’s the command to run to fix it:
sudo aptitude update; sudo aptitude purge sysstat -y; sudo aptitude install sysstat -y; sudo sed -i "s/ENABLED="false"/ENABLED="true"/" /etc/default/sysstat; sudo /etc/init.d/sysstat start /
The lines from top to bottom update the repo list, remove sysstat and purge it’s settings, install sysstat, set the sysstat config file to true so it runs, then start the sysstat daemon.
It should be rocking again after that 🙂
root@server1:/var/log/sysstat# sar Linux 3.8.4-x86_64 (server1) 04/19/2013 _x86_64_ (8 CPU) 08:59:15 AM LINUX RESTART