similar to: Scaling to 10 Million IMAP sessions on a single server

> On Feb 21, 2017, at 11:12 PM, Christian Balzer <chibi at gol.com> wrote: > > On Tue, 21 Feb 2017 09:49:39 -0500 KT Walrus wrote: > >> I just read this blog: https://mrotaru.wordpress.com/2013/10/10/scaling-to-12-million-concurrent-connections-how-migratorydata-did-it/

> 1. 256GB of real RAM, swap is for chums. Are you sure that 100,000 IMAP sessions wouldn?t work well with SWAP, especially with fast SSD storage (which is a lot cheaper than RAM)? Seems that these IMAP processes are long lived processes (idling most of the time) that don?t need that much of the contents of real memory available for much of the life of the process. I use a database proxy in

Thanks for the info. I do have one further question for you. On your servers that are currently handling 50k IMAP sessions, how many users does that correspond to? Since many users will have multiple IMAP sessions on multiple devices, I?d like to hear about some real-world numbers that could be used for budgeting a new project like mine. Also, do you use Dovecot IMAP proxies in front of your

On Tue, 21 Feb 2017 09:49:39 -0500 KT Walrus wrote: > I just read this blog: https://mrotaru.wordpress.com/2013/10/10/scaling-to-12-million-concurrent-connections-how-migratorydata-did-it/ <https://mrotaru.wordpress.com/2013/10/10/scaling-to-12-million-concurrent-connections-how-migratorydata-did-it/> about scaling to 12 Million Concurrent Connections on a single server and it got me

thanks for your help happy to say that the performance dramatically improved after i use the high performance settings from here http://wiki.dovecot.org/LoginProcess grep Login: /var/log/mail.log.1 |wc -l with the mail.log being of a typical, busy day. 412992 i also picked up the imap and pop3 connections during peak hours [root at ns1 domains]# doveadm who | awk

christian the servers i currently own are dell servers. The servers i plan to buy are Dell R530, 2U rack servers with 8 x 3.5 inch drives, with 64 gb ram each, Hardware raid. I am thinking of 2 X 300 gb ssds raid1 and 6 x 2 tb drives in raid10 for data. I do not have any experience in setting up drdb (that would be my next step) ... primarily using standalone servers with hardware level

> 1500 IMAP sessions will eat up about 3GB alone. Are you saying that Dovecot needs 2MB of physical memory per IMAP session? If I want to support a max 100,000 IMAP sessions per server, I should configure the server to have at least 200GBs of SWAP? > On Feb 10, 2017, at 3:58 AM, Christian Balzer <chibi at gol.com> wrote: > > On Fri, 10 Feb 2017 01:13:20 +0530 Rajesh M wrote:

On Fri, 03 Jul 2015 07:05:43 +0200 Urban Loesch wrote: > Hi, > > Am 03.07.2015 um 05:14 schrieb Christian Balzer: > > > > > 2. Here is where the fun starts. > > Each IMAP session that gets proxied to the real mailbox server needs a > > port for the outgoing connection. > > So to support 2 million sessions we need 40 IP addresses here. Ouch. > >

Hello, first post in 3 years, kinda shows how painless Dovecot is. ^o^ Also this isn't really a dovecot issue, alas it's involved and since there are some large scale implementations of it I hope somebody here has some insights I might have missed. Currently we're running this setup: 1. LVS (DR mode) in a HA configuration (2 node cluster) 2. Dovecot in proxy mode on a 2 node

Hello, We've got a pretty substantial dovecot installation (versions 2.1.7 and 2.2.13 on the backends, but tested with 2.2.24 as well) and this is the relevant config snippet from 10-master.conf: --- default_process_limit = 1024 default_client_limit = 16384 [...] service imap { # Most of the memory goes to mmap()ing files. You may need to increase this # limit if you have huge

Hello, Dovecot 2.2.27 (Debian Jessie backports). When issuing a "doveadm kick" for a specific user I was greeted by: --- "warning: other connections would also be kicked from following users:" --- and a list of 22odd thousand users. As it turns out, kick wants to smack the hibernation proces(ses) that have hibernated sessions for this user, obviously the wrong approach here.

Hello, I'm willing to swear that with the 0.99.10.4 Debian package in my rather extensive tests with mailbox format dovecot created not only any missing parental directories but also the INBOX file, but the later I can't prove/test now as I upgraded all respective boxes. However 0.99.10.5 will still create (if needed and possible) missing directories for mbox storage, just not an

Hello, running 0.99.10.6 (but seen it before that, too). Also (quite obviously) running 5 auth processes, given the fact that this is a pretty busy box and I didn't want to introduce any artificial bottlenecks. Alas with them eating up half of the free memory (which would go to a much better use as FS cache) I'm getting sorta concerned. If it's not a leak, it's caching something

On 6 Apr 2017, at 9.56, Christian Balzer <chibi at gol.com> wrote: > >> For no particular reason besides wanting to start conservatively, we've got >> client_limit set to 50 on the hibernate procs (with 1100 total hibernated >> connections on the box I'm looking at). At only a little over a meg each, >> I'm fine with those extra processes. >>

Hello, Just to follow up on this, we've hit over 16k (default client limit here) hibernated sessions: --- dovecot 119157 0.1 0.0 63404 56140 ? S Apr01 62:05 dovecot/imap-hibernate [11291 connections] dovecot 877825 0.2 0.0 28512 21224 ? S Apr23 1:34 dovecot/imap-hibernate [5420 connections] --- No issues other than the minor bug I reported, CPU usage is

Hi, I've very old Dovecot version so I'm trying to migrate new disk and current version of dovecot. But POP3 accounts have "version 1" .INBOX/dovecot-uidlist files so clients download the messages again. How can achieve not to download to mailbox after copy to new disk? Is there any script or something to migrate index v1 to v3? thanks for your suggestions.

----- Original Message ----- From: Christian Balzer [mailto:chibi at gol.com] To: dovecot at dovecot.org Cc: 24x7server at 24x7server.net Sent: Fri, 10 Feb 2017 17:58:58 +0900 Subject: On Fri, 10 Feb 2017 01:13:20 +0530 Rajesh M wrote: > hello > > could somebody with experience let me know the dovecot config file settings to handle around 1500 simultaneous connections over pop3 and

We've been using hibernate for about half a year with no ill effects. There were various logged errors in earlier versions of dovecot, but even with those, we never heard a reported customer-side error (almost always when transitioning from hibernate back to regular imap; in the case of those errors, presumably the mail client just reconnected silently). For no particular reason besides

Hello, On Thu, 6 Apr 2017 09:24:23 +0300 Aki Tuomi wrote: > On 06.04.2017 07:02, Christian Balzer wrote: > > > > Hello, > > > > this is on Debian Jessie box, dovecot 2.2.27 from backports, > > imap-hibernate obviously enabled. > > > > I've been seeing a few of these since starting this cluster (see previous > > mail), they all follow the

Hello, just to soothe my paranoia from many years of qpopper usage, which enforces solitary access to a POP mailbox. Only one login per user is possible at the same time and if a session terminates w/o qpopper being properly notified it will remain locked for some time, 30 minutes by default. With dovecot (0.99.10.4) one can login multiple times (using POP, with IMAP of course this comes as