Why not skip 8 and go straight to 9?
Are you sure it is not difference in db engine in openldap? When I import my records I also need to change the config with an ldif to get better performance during slapadd
We are working on moving from openldap2.4.44 to symasldap2.6.7. We have total of 13million docs.
centos7 to centos7 is taking 1~2hours where as rocky8 is taking 48hours and more.
Settings of centos7 and rocky8 are identical. We are moving to rocky8 as centos7 is EOL.