Hi, I'm using FreeRADIUS Version 3.0.4, for host x86_64-redhat-linux-gnu on Centos_7 I'm using server with 4GB RAM, 4xCPU, 50GB Disk and 100% FreeRadius dedicated The database MariaDB 10.x is running on a different server with more RAM and CPU. I've changed radiusd.conf with: max_requests = 2500000 max_servers = 256 max_spare_servers = 400 I have 10.000 test users connectes with PPoE with 5 minutes timeout and interim every 1 minute. I have this Errors on log: 1) Error: rlm_sql_mysql: MySQL error 'Duplicate entry 'e35620bfd04391bc9c6f5afe3628449d' for key 'acctuniqueid'' Fri Nov 20 00:10:14 2015 : Error: rlm_sql (sql): Duplicate entry 'ab0c9cb893d6af4de3388749d7004c2b' for key 'acctuniqueid' Fri Nov 20 00:10:14 2015 : Error: rlm_sql_mysql: Cannot store result Fri Nov 20 00:10:14 2015 : Error: rlm_sql_mysql: MySQL error 'Duplicate entry 'ab0c9cb893d6af4de3388749d7004c2b' for key 'acctuniqueid'' Fri Nov 20 00:10:14 2015 : Error: rlm_sql (sql): Duplicate entry '8902d57334a046e00c6231ad91aad63e' for key 'acctuniqueid' Fri Nov 20 00:10:14 2015 : Error: rlm_sql_mysql: Cannot store result Fri Nov 20 00:10:14 2015 : Error: rlm_sql_mysql: MySQL error 'Duplicate entry '8902d57334a046e00c6231ad91aad63e' for key 'acctuniqueid'' Fri Nov 20 00:10:23 2015 : Error: rlm_sql (sql): Duplicate entry '4b5b0717c9b3c5f2100ff001efa9f6b3' for key 'acctuniqueid' Fri Nov 20 00:10:23 2015 : Error: rlm_sql_mysql: Cannot store result Fri Nov 20 00:10:23 2015 : Error: rlm_sql_mysql: MySQL error 'Duplicate entry '4b5b0717c9b3c5f2100ff001efa9f6b3' for key 'acctuniqueid'' 2) Fri Nov 20 00:16:25 2015 : Error: rlm_sql (sql): Cannot open new connection, connection spawning already in progress Fri Nov 20 00:16:25 2015 : Warning: rlm_sql (sql): 21 of 21 connections in use. You probably need to increase "spare" Fri Nov 20 00:16:25 2015 : Error: rlm_sql (sql): Cannot open new connection, connection spawning already in progress Fri Nov 20 00:16:25 2015 : Warning: rlm_sql (sql): 22 of 22 connections in use. You probably need to increase "spare" Fri Nov 20 00:16:25 2015 : Info: rlm_sql (sql): Opening additional connection (543) Fri Nov 20 00:16:25 2015 : Warning: rlm_sql (sql): 22 of 22 connections in use. You probably need to increase "spare" Fri Nov 20 00:16:25 2015 : Error: rlm_sql (sql): Cannot open new connection, connection spawning already in progress 1) As Alan Dekok told this duplicate key error is because FreeRadius 3.0.4 . but I'm not able to compile and install newer version because is not on the Centos_7 repository .. Is there any PATCH or file I can modify to fix this error ? 2) I modify max_spare_server to 400 and still you probably need to increase spare . wich value do you think could be ok ? Do I need to modify any other value ? Thanks a lot !