Information
The backlog limit has a default setting of 64
Rationale:
during boot if audit=1, then the backlog will hold 64 records. If more that 64 records are created during boot, auditd records will be lost and potential malicious activity could go undetected.
Solution
Edit /etc/default/grub and add audit_backlog_limit=<BACKLOG SIZE> to GRUB_CMDLINE_LINUX:
Example:
GRUB_CMDLINE_LINUX='audit_backlog_limit=8192'
Run the following command to update the grub2 configuration:
# update-grub