Re: [Dovecot] Ongoing performance issues with 2.0.x
Ralf Hildebrandt put forth on 11/5/2010 4:23 AM: Due to the ongoing performance issues with 2.0.x I switched back to 1.2.15 yesterday evening, with no changes to the machine or my users. (I migrated from 1.2.15 to 2.0.x by converting the existing config) Today, we have MUCH LESS load, with the same number of logins/min. I cannot say what exactly causes this immense increase in load, but one observation is that the time spent in system() has now dropped (user and iowait have stayed contant) to a third of the values I was seeing with 2.0.x. This evening I'll post some graphs showing two comparable 24 hour ranges. Hi Ralf, What hardware platform? (AMD/Intel/SPARC/PPC, generation/freq) What OS platform? What compiler/version? What threading library? If IPC is the culprit, it may very well be a platform/compiler/system library issue and not a dovecot issue, given no one else seems to be suffering this problem. -- Stan
Re: [Dovecot] Ongoing performance issues with 2.0.x
* Daniel L. Miller dmil...@amfes.com: Dunno if you ever mentioned it - or if it makes any difference - but what configure/build options are you using for 1.2 vs 2.0? Any difference in the compiler? Is your 1.2 a distro pre-packaged binary? No, both have been compiled from source using these options: ./configure --enable-maintainer-mode (dovecot2 uses ./configure --prefix=/usr/dovecot-2 --enable-maintainer-mode since I need to install it someplace else) both using gcc version 4.4.5 (Debian 4.4.5-2) -- Ralf Hildebrandt Geschäftsbereich IT | Abteilung Netzwerk Charité - Universitätsmedizin Berlin Campus Benjamin Franklin Hindenburgdamm 30 | D-12203 Berlin Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962 ralf.hildebra...@charite.de | http://www.charite.de
Re: [Dovecot] Ongoing performance issues with 2.0.x
* Stan Hoeppner s...@hardwarefreak.com: What hardware platform? (AMD/Intel/SPARC/PPC, generation/freq) Intel(R) Xeon(R) CPU L5335 @ 2.00GHz What OS platform? Debian lenny What compiler/version? gcc version 4.4.5 (Debian 4.4.5-2) What threading library? ? how do I find out? If IPC is the culprit, it may very well be a platform/compiler/system library issue and not a dovecot issue, given no one else seems to be suffering this problem. -- Ralf Hildebrandt Geschäftsbereich IT | Abteilung Netzwerk Charité - Universitätsmedizin Berlin Campus Benjamin Franklin Hindenburgdamm 30 | D-12203 Berlin Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962 ralf.hildebra...@charite.de | http://www.charite.de
Re: [Dovecot] Ongoing performance issues with 2.0.x
Ralf Hildebrandt put forth on 11/6/2010 9:15 AM: * Stan Hoeppner s...@hardwarefreak.com: What hardware platform? (AMD/Intel/SPARC/PPC, generation/freq) Intel(R) Xeon(R) CPU L5335 @ 2.00GHz What OS platform? Debian lenny What compiler/version? gcc version 4.4.5 (Debian 4.4.5-2) Hmm. My Lenny systems have 4.3.2-2. Are you maybe using Squeeze, not Lenny? I'm still using i686 systems, but I wouldn't think that would change the version of GCC that gets installed. I'm not sure if this may be playing a role in this problem or not. What kernel version are you running, stock Debian or rolled from source? What threading library? ? how do I find out? I was mainly asking that in case your platform was something other than x86. With Linux you should be using NPTL for threading. This shouldn't be a problem. I'm trying to help you identify what is different on your system from other OPs that is causing 2.x to perform so badly vs 1.x. If sys is high but usr and iowait aren't, then I would think the problem is in a system library, your kernel, dovecot, or more specifically, the interaction among all three. You're using maildir correct? What filesystem are you using? Are you doing anything in your Dovecot config, both 1.x and 2.x, that is unique or non-standards maybe, compared to other OPs? Is this a virtual machine guest or bare metal host? What do memory and swap usage look like? What do you see for %CPU when you watch your kernel threads in top? Is one of then eating lots of CPU time? If so, which one? -- Stan
Re: [Dovecot] Ongoing performance issues with 2.0.x
* Stan Hoeppner s...@hardwarefreak.com: Hmm. My Lenny systems have 4.3.2-2. Are you maybe using Squeeze, not Lenny? Yes, squeeze, sorry I'm still using i686 systems, but I wouldn't think that would change the version of GCC that gets installed. I'm not sure if this may be playing a role in this problem or not. What kernel version are you running, stock Debian or rolled from source? 2.6.32-23-generic-pae, from Ubuntu I'm trying to help you identify what is different on your system from other OPs that is causing 2.x to perform so badly vs 1.x. If sys is high but usr and iowait aren't, then I would think the problem is in a system library, your kernel, dovecot, or more specifically, the interaction among all three. You're using maildir correct? What filesystem are you using? Maildir on ext4 Are you doing anything in your Dovecot config, both 1.x and 2.x, that is unique or non-standards maybe, compared to other OPs? It's all users from /etc/passwd, but nothing special. Is this a virtual machine guest or bare metal host? virtual machine guest What do memory and swap usage look like? Memory usage is identical with 2.0 and 1.2: total: 8GB free: 5457MB cached: 1054MB The machine has no swap. What do you see for %CPU when you watch your kernel threads in top? Is one of then eating lots of CPU time? If so, which one? Uhm, for that I'd have to switch back and look at kernel threads explicitly. -- Ralf Hildebrandt Geschäftsbereich IT | Abteilung Netzwerk Charité - Universitätsmedizin Berlin Campus Benjamin Franklin Hindenburgdamm 30 | D-12203 Berlin Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962 ralf.hildebra...@charite.de | http://www.charite.de
Re: [Dovecot] Ongoing performance issues with 2.0.x
* Ralf Hildebrandt ralf.hildebra...@charite.de: I'm still using i686 systems, but I wouldn't think that would change the version of GCC that gets installed. I'm not sure if this may be playing a role in this problem or not. What kernel version are you running, stock Debian or rolled from source? 2.6.32-23-generic-pae, from Ubuntu I'm using this one because the bigmem kernels in Debian had some problems (being: bigmem not working at all, it was not compiled in) -- Ralf Hildebrandt Geschäftsbereich IT | Abteilung Netzwerk Charité - Universitätsmedizin Berlin Campus Benjamin Franklin Hindenburgdamm 30 | D-12203 Berlin Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962 ralf.hildebra...@charite.de | http://www.charite.de
Re: [Dovecot] Ongoing performance issues with 2.0.x
Ralf Hildebrandt put forth on 11/6/2010 10:33 AM: * Ralf Hildebrandt ralf.hildebra...@charite.de: I'm still using i686 systems, but I wouldn't think that would change the version of GCC that gets installed. I'm not sure if this may be playing a role in this problem or not. What kernel version are you running, stock Debian or rolled from source? 2.6.32-23-generic-pae, from Ubuntu I'm using this one because the bigmem kernels in Debian had some problems (being: bigmem not working at all, it was not compiled in) And I'm guessing you're running a 32bit PAE kernel because VMWare ESX still doesn't officially support 64bit guests, correct? Or are you using another hypervisor that also has such a limitation? Is this the only guest on this host or do you have others? If this is the only guest, you have 2 dual core dies in that Xeon CPU, 4 cores total. I assume you've assigned 4 virtual CPUs to this Debian VM? You may want to run top in the hypervisor console itself (or an SSH session into the hypervisor) and watch the %CPU of the hypervisor's kernel threads. That might tell us something as well. -- Stan
Re: [Dovecot] Last login tracking with login_executable
On Thu, Oct 14, 2010 at 03:38:04PM +0100, Ed W wrote: On 14/10/2010 15:04, Denny Lin wrote: I was wondering if it would be possible to read the username/password from a Dovecot config file (like userdb/passdb/quota/expire) instead of using my.cnf. In that case I think just creating a script with the password in it, which is itself called from login process does what you need? (As Timo just said) In Dovecot 2 there is a move to splitting the config files up to a greater extent, so I think it can be seen really as an extension of that if you have one more file knocking around? However, do still remember that you should almost certainly create a separate database user for this task - this user can then be locked down (eg only insert access to a single table) and in that way there is a limit to the damage they could do even if the password were compromised? I like people who think about security though - please consider writing up your final solution on that page of the wiki so that there is a best practice solution on there? Sorry for the late reply. I've been very busy recently (filling out university applications). In the end I decided to use Timo's solution as it seems like the best one. Thanks for all the advice and suggestions. -- Denny Lin
