linux IMAP and IDLE

Post #312,706 by boxley 8/18/09 1:22:45 PM Reply	linux IMAP and IDLE having to do a little idling. Since the protocol will keep a connection open continiously, on a linux box how many simultaneous connections can I hold open without NIC/IP degradation? thanx, bill
Post #312,707 by folkert 8/18/09 2:11:54 PM Reply	Sometimes... I have in excess of 15,000 connections on our mail server, various stages of connections. See little IF ANY performance degradation. The only time I see degradation is when multiple connections are pulling lots and lots of data at the same time... Idle/persistent connections... pretty much take very little memory and processing to handle. We are talking a very very significant number to hurt any modern machines. (Modern being anything newer than 4-5 years old)
Post #312,708 by boxley 8/18/09 2:22:26 PM Reply	the kernel limit is 64K correct?
Post #312,724 by folkert 8/18/09 5:11:32 PM 8/18/09 5:12:00 PM Reply	Re: the kernel limit is 64K correct? That used to be the limit in the 2.2 Kernels... I believe 2.4 was much higher and I think 2.6 is again way higher. In any case it there were a limit, it would be PER IP address on the physical connection. The local PORT range absolute maximum is 65535 lowest is 0. Come to think of it... we have Linux firewalls and regularly we have many many many thousands of connections through it, which count. We average 32K connection on a busy day not counting REALLY busy days. We have surpassed the 64K threshold regularly. Today we are at about 10K at any one moment. typo: wrong word... Edited by folkert Aug. 18, 2009, 05:12:00 PM EDT Expand All History
Post #312,726 by folkert 8/18/09 6:10:21 PM Reply	Also, depending on what you are using... The program is what is limiting you. Based on maximum per process file descriptors. I have bumped into openLDAP in CentOS v5.x being compiled with 1024 max file descriptors... and having to recompile for much higher. So really it depends on the supporting program on which the connection is to.
Post #312,728 by boxley 8/18/09 7:01:10 PM Reply	that part is high end no worries there. Just with the IDLE command tying up connections I wanted to make sure I could scale when we release it

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