#260: OpenLDAP directory service ---------------------------------------+------------------------------------ Reporter: jusiskin@… | Owner: sagen@… Type: Feature | Status: new Priority: 2: Expected | Milestone: CalendarServer-2.x Component: Calendar Server | Severity: Other Keywords: | ---------------------------------------+------------------------------------ Comment(by rahul@…): I have figured out the problem. I could probably say the problem is with the client (Thunderbird beta+Lightning). When connection to the calendar server fails because the username does not exist or if the authentication fails because the wrong password was saved in Thunderbird, the client should stop connecting (or try after some time). But instead it kept on trying to reconnect which affected the calendar server in two ways: 1. The major affect was when clients which were configured with usernames not existing in the ldap directory kept trying to connect. As the username was not found in the cache, the entire cache for users was being refreshed by the ldap patch in this page. And as the client kept on trying to reconnect upon failure, the cache was refreshed continuously which increased the cpu usage tremendously. 2. Also upon authentication failure, the client kept retrying which also lead to an increase in CPU usage. But this overload was not as high as in the previous case. The obvious fix is to fix the code with client (Thunderbird and/or Lightning). When connection fails 2 or 3 times for whatever reason (username does not exist, wrong password entered, etc.), connection attempts should be stopped. Also some code modification could be done on the server side to limit connections from such misconfigured clients so that other users do not face any inconvenience because of these small number of badly configured clients Replying to [comment:34 rahul@…]:

I would like to know whether anyone is using this patch in a production environment. I am using this patch with calendarserver in a company with about 250 users simultaneously connected with Lightning. The error log shows that authentication has failed for about 4-5 users and it keeps on retrying continuously. The calendar server process initially starts normally but suddenly its cpu usage goes to above 90%.

The server is a Intel Core 2 1.86 Ghz CPU with more than 3 GB RAM.

I am trying to figure out the possible reason for the high CPU usage.

1. The server configuration is not sufficient for 250 simultaneous users. 2. The ldap patch is coded in a way which is leading to the high CPU usage. 3. The repeated authentication attempts is leading to the high CPU usage.

Any help in this regard would be highly appreciated.

-- Ticket URL: <http://trac.calendarserver.org/ticket/260#comment:35> CalendarServer </> HTTP/WebDAV/CalDAV Server