- dovecot - dovecot.org

Re: How to reduce the number of UNIX sockets?
by Joseph Tam 05 Oct '23

05 Oct '23

From: Steve Litt <slitt(a)troubleshooters.com> > Recently I've been getting the dreaded X error "Maximum number of > clients exceeded", so I performed an lsof -U to find who was using > UNIX sockets. This uncovered a buggy looping program I wrote using up > gobs of UNIX sockets, along with some browsers, dbus-daemon, electron > (used by vscode), smbd, and Dovecot, which uses 36 UNIX sockets. Only 36? The number of sockets seems to scale proportionally with the number of users. The login process of my service easily consumes several hundred sockets and could on occasions run into the thousands. (See also my previous posts on socket starvation.) Each client connection will consume a few sockets -- it uses maybe a few more than some applications do as they separate privileged daemons from worker daemons, and pass data around via sockets, but socket use if within reason. > I can kill dbus-daemon and the buggy program I wrote, minimize use of > browsers, disable smbd except when I (rarely) need it, but can you > think of things I can do to reduce the number of UNIX sockets used by > Dovecot on my machine? You can limit the number of clients per IP (e.g. mail_max_userip_connections) to lower the number of concurrent mailboxes that are open. Or use the idle process facility to park inactive connections (not sure if that frees sockets). Or cap the number of clients (process_limit, service_count, etc.), but if you're bumping up against those limits, you've either underprovisioned your service or you have something misconfigured. (Again, see my previous post on service_limit.) Maybe you need to *increase* those limits if you're hitting some client limit in regular use. From what you describe, you resolved the cause of your socket starvation whose cause was not dovecot. I'm not sure what you hope to gain by saving a few sockets that dovecot uses just to make headroom for a buggy script. Joseph Tam <jtam.home(a)gmail.com>

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How to reduce the number of UNIX sockets?
by Steve Litt 04 Oct '23

04 Oct '23

Hi all, I'm using Dovecot version 2.3.21 on an up to date Void Linux on a 6 core 12 thread Ryzen with 48GB RAM, 1TB NVMe, and 12TB of 7200 RPM spinning rust hard drives. Recently I've been getting the dreaded X error "Maximum number of clients exceeded", so I performed an lsof -U to find who was using UNIX sockets. This uncovered a buggy looping program I wrote using up gobs of UNIX sockets, along with some browsers, dbus-daemon, electron (used by vscode), smbd, and Dovecot, which uses 36 UNIX sockets. I can kill dbus-daemon and the buggy program I wrote, minimize use of browsers, disable smbd except when I (rarely) need it, but can you think of things I can do to reduce the number of UNIX sockets used by Dovecot on my machine? Thanks, SteveT Steve Litt Autumn 2023 featured book: Rapid Learning for the 21st Century http://www.troubleshooters.com/rl21

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Plugin to cleanup/remove unused user defined keywords(IMAP PERMANENTFLAGS) possible ?
by sergey＠srgdev.com 03 Oct '23

03 Oct '23

I found a reference to a similar issues here: https://www.dovecot.org/list/dovecot/2010-March/047925.html I know IMAP rfc say nothing about removing the keywords/PERMANENTFLAGS (they can only be added https://www.rfc-editor.org/rfc/rfc3501.html#page-64) , therefore I wonder if it is possible to create a Dovecot plugin to accomplish this task ? Technically it is possible to do now via the following steps: 1. Ensure the "unwanted" user defined keyword/flag is remove from all messages in a folder (Folder A) 2. Create a temporary folder (Folder A_temp) 3. Move all messages from Folder A -> Folder A_temp 4. Delete Folder A 5. Rename Folder A_temp -> Folder A As you can see this highly inefficient and awkward and even if the unwanted keyword does NOT appear in Folder A anymore , it still can be found in '~/Maildir/dovecot-keywords' file Alternatively, if it is hard to create a plugin that would remove the keyword for good, would something like this be easier: 1. Define a list of "allowed" user defined keywords 1a. Perhaps this list can be defined via METADATA extension on per folder basis 2. Reject(or discard) "not allowed" keyword sent via the +FLAGS / +FLAGS.SILENT commands Any helpful plugin example or code references would be greatly appreciated. Thank you very much, Sergey Mosin

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Dovecot List server
by Paul Enlund 03 Oct '23

03 Oct '23

Hi Is there a contact address for operation of this list server. I have some observations regarding ARC signing to share. Regards Paul

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Ping
by Paul Enlund 03 Oct '23

03 Oct '23

just a test sorry for noise _______________________________________________ dovecot mailing list -- dovecot(a)dovecot.org To unsubscribe send an email to dovecot-leave(a)dovecot.org

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Compression: all or nothing?
by Alex King 03 Oct '23

03 Oct '23

Using 2.3.13 (89f716dc2) (debian package), with mdbox storage. I considering adding the zlib plugin. I understand that reading mail can cope with either compressed or uncompressed mailboxes. I'm wondering if I can leave the main storage uncompressed, while having the alternate storage compressed. There does not seem to be a way to configure this, from https://doc.dovecot.org/settings/plugin/zlib-plugin/ it seems compression (on saving emails) is an all-or-nothing option? Can I leave zlib_save unset in my main configuration, and have doveadm use some alternate configuration with zlib_save set? It doesn't look hopeful because I don't see the ability to use a different config at https://wiki.dovecot.org/Tools/Doveadm/Altmove. Perhaps I would need multiple copies of the daemon running? Or is it better just to compress everything? I plan to store older mails (perhaps 3months+) in the alternative storage, and was thinking it would be nice to have those compressed, while I don't need to compress the main store. Any feedback welcome. Thanks, Alex

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Ping
by Paul Enlund 02 Oct '23

02 Oct '23

just a test sorry for noise

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Re: Changed separator, sub folders not showing new e-mail
by Francis Augusto Medeiros-Logeay 02 Oct '23

02 Oct '23

I found the answer here: https://apple.stackexchange.com/questions/441313/no-mailbox-doesnt-exist-se… Apparently on Mac one needs to update the separator on a file, since it doesn’t seem that the Mail.app does it for itself. On the iPhone it happened automatically. Best, Francis

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Changed separator, sub folders not showing new e-mail
by Francis Augusto Medeiros-Logeay 02 Oct '23

02 Oct '23

Hi, I recently changed the mailbox separator from '.' to '/' so that I could have shared mailboxes working. However, while the mailboxes show fine on Roundcube and on other web-based e-mail clients, on the Mail.app on my Mac I don't get newer messages on those sub folders. For example, I have a subfolder Test. Mails filtered to be dropped there, show fine. But I have one called Lists, with a sub folder called "Dovecot". I can't read mails that are under "Lists/Dovecot". Can anyone help? Best, Francis -- Francis Augusto Medeiros-Logeay Oslo, Norway

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Separators and shared namespaces
by Francis Augusto Medeiros-Logeay 28 Sep '23

28 Sep '23

Hi Martin, I had a similar problem: https://dovecot.org/mailman3/archives/list/dovecot@dovecot.org/thread/DNHM3… It seemed to me that using ‘.’ truncated the domain name when that was used in the paths, such as when using %d. Best, Francis

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