You need to make a small change in the file /etc/cron.d/sysstat. You need root access to make these changes.
"debian-sa1" has become only "sa1" in Debian 11. "sa1" collects and stores binary data in the system activity daily data file. So, you need to replace "debian-sa1" with "sa1" in the file.
- Open the file /etc/cron.d/sysstat; you will find lines similar to the following lines.
# Activity reports every 10 minutes everyday
5-55/10 * * * * root command -v debian-sa1 > /dev/null && debian-sa1 1 1
# Additional run at 23:59 to rotate the statistics file
59 23 * * * root command -v debian-sa1 > /dev/null && debian-sa1 60 2
- Replace "debian-sa1" with "sa1"
- Restart sysstat using command "systemctl restart sysstat".
It should fix the issue, and the sar command should show the report.