similar to: dovecot config for 1500 simultaneous connection

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

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

> 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

> 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:

Hello, On Fri, 10 Feb 2017 14:50:03 -0500 KT Walrus wrote: > > 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)? > I'm sure about tax and death, not much else. But as a rule of thumb I'd avoid swapping out stuff on production servers,

----- 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

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, 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

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. >>

Daniel, thanks so much for the detailed pointers. So it turns out to be both the evil that is systemd and an overzealous upgrade script. Apollon, should I raise a Debian bug for this? As for reasons, how do 50k proxy session on the proxy servers and 25k imap processes on the mailbox servers sound? Even on a server with just 6k users and 7k imap processes that causes a massive load spike and a

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

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

On Fri, 10 Feb 2017 07:59:52 -0500 KT Walrus wrote: > > 1500 IMAP sessions will eat up about 3GB alone. > > Are you saying that Dovecot needs 2MB of physical memory per IMAP session? > That depends on the IMAP session, read the mailbox size and index size, etc. Some are significantly larger: --- PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND

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 thinking. Would it be possible to scale Dovecot IMAP server

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, 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 same pattern, a user who accesses their mailbox with both POP3 and IMAP deletes mails with POP3 and the IMAP (imap-hibernate really) is getting confused and upset about this: --- Apr 6

Hello, as the tin says. I have several servers running 2.2.27 (Debian stretch) and am adding new ones with 2.3.4.1 (Debian buster). The configs were upgraded where needed but neither 10-mail.conf nor 15-mailboxes.conf were changed. 15-mailboxes is all commented out (I guess the default is auto-create, which isn't documented anywhere I could find) and the only non-comments in 10-mail.conf are

Hello, Both the examples on the Push Notification wiki page and the XAPS plugin docs seem to suggest or state that LMTP/LDA is required. However IMAP IDLE notifications work without either of these (please no religious discussion of why Dovecot LMTP is the best thing since sliced bread and that everybody should use it). The LUA part of the push notification docs however states that events other

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, 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