Shekhar S wrote:
Thanks for your response. It’s Connection Timeout. Some additional info - i just went ahead and for sake of trying updated the olcthread value to 1750 and post that was able to get 1650 concurrent connections working concurrently consistently, but anything beyond that again randomly threw connection timeout errors.
Since you're using back-meta, the limit is most likely on the target LDAP server.
One more thing you can try is to increase olcListenerThreads (no more than the number of CPUs). But since raising olcThreads affects your result, clearly the remote server is keeping slapd's threads tied up waiting for responses.
You can also use back-asyncmeta in OpenLDAP 2.5 for better behavior without needing thousands of slapd threads, but the end result will be the same - it can only answer as fast as the remote server and no faster.
Message sent from a mobile device, please excuse typos and brevity.
On Sep 13, 2021, at 9:28 PM, Howard Chu firstname.lastname@example.org wrote:
Was load testing against openldap (slapd-meta) where we were trying to submit 1000 concurrent bind requests. This was done using the JMeter load testing tool. In every run approximately only 420-430 bind requests are successful and remaining 500+ bind requests fail with "Communication Exception" error. We also tried with 500 bind requests and the result was somewhat same - 420 odd successful and 70-80 failed with communication exception.
What does a "Communication exception" actually mean? Connection refused, connection timed out, what?
We've tested tens of thousands of concurrent connections with slapd. It is unlikely to be the problem here.
We have openldap 2.4.56 installed on a RHEL 8.1 host with 32GB memory and 8CPU. We have configured max open files for the slapd process to be 65K .
Our requirement is to support 6000 concurrent requests at minimum. Is there any configuration that can be tweaked to support this amount of concurrent load ? I do see "olcConcurrency" & "olcThreads" set to 0 and 16 respectively. Should we be tweaking these to support the required load, if yes what should be the values for those ? Please assist. Thank you for your help !