nixos/slurm: add recommended mysql settings

nixos/tests/slurm.nix

@@ -63,6 +63,12 @@ in {
             ensurePermissions = { "slurm_acct_db.*" = "ALL PRIVILEGES"; };
             name = "slurm";
           }];
+          extraOptions = ''
+            # recommendations from: https://slurm.schedmd.com/accounting.html#mysql-configuration
+            innodb_buffer_pool_size=1024M
+            innodb_log_file_size=64M
+            innodb_lock_wait_timeout=900
+          '';
         };
       };