Hello. I would like to kindly ask for help with freeradius server processing Accounting req. I am running freeradius 3.0.11 on Debian stable, kernel 3.16.0-4-amd64. Server is DL380 G9, CPU E5-2680 v3 @ 2.50GHz, 256GB RAM, very fast HP SSD RAID5 2.5 TB. The kernel can see 48 CPU. Radius is processing ~ 3kqps of Accounting (Telco environment). The daemon receives Acct. req. and using module rml_detail it writes it into a detail file(s) - there are 32 file queues based on modulo of Calling-Station-Id. detail detail.mobile { Queue-Number = "%{expr: %{Calling-Station-Id} %% 32 }" filename = ${radacctdir}/detail.mobile_v3/queue-${Queue-Number}/detail-%Y%m%d%H locking = yes } Then there are detail file loaders into DB: server buffered-sql-0 { listen { type = detail filename = "${radacctdir}/detail.mobile_v3/queue-0/detail-*" load_factor = 95 track = yes poll_interval = 1 retry_interval = 60 } preacct { } accounting { sql_instance_mobile if (noop) { ok } } } Some server params: max_request_time = 10 cleanup_delay = 5 max_requests = 20000 hostname_lookups = no max_servers = 1500 min_spare_servers = 100 max_spare_servers = 300 Everything works fine, there is ~15 connections to DB while processing ~2-3 kqps. Freeradius utilize about 3 CPU. This setup can load gigs of logs into DB without slowing down Radius responses. The issue is that freeradius randomly starts to use too much CPU (60-70% of whole server). There are following lines appearing in the log: Wed Mar 29 09:17:43 2017 : WARNING: (44056176) WARNING: Module rlm_detail became unblocked for request 44056176 Wed Mar 29 09:17:43 2017 : WARNING: (44056177) WARNING: Module rlm_detail became unblocked for request 44056177 Wed Mar 29 09:17:43 2017 : WARNING: (44056178) WARNING: Module rlm_detail became unblocked for request 44056178 Wed Mar 29 09:17:43 2017 : WARNING: (44056179) WARNING: Module rlm_detail became unblocked for request 44056179 Wed Mar 29 09:17:43 2017 : WARNING: (44056180) WARNING: Module rlm_detail became unblocked for request 44056180 It seems to be related to high spikes in the incoming radius traffic that occurs every hour - the issue become worse after DST change when certain amount of terminal were restarted in the same moment and their sessions produce Radius Accounting synchronously. But not every time. I have an old server doing the same thing running Freeradius 3.0.8., the kernel can see 24 CPU, and it really never happened here while on the new box it is on daily basis. The configuration of Radius is identical. Thanks Regards Ales