[Dovecot] Apple Mail and too many open files?

[Alan Schmitt]

On 24 mai 06, at 11:55, Rob Middleton wrote:

> You need to look at the parameters:
> sysctl -a
> kern.maxfiles = 12288
> kern.maxfilesperproc = 10240
> and fix them by creating a file /etc/sysctl.conf

Ah, thanks, this is good to know.

> OS X is configured by default with these numbers way too low. OS X  
> has some really dumb processes like AFP that will chew through all  
> of your open files and not cope cleanly with running out of  
> allowable/available filehandles.
>
> OS X has a DoS vulnerability in the way ssh processes are spawned  
> and the ssh interaction with their PAM modules (it exhibits with  
> the symptoms you have described). Have you really got port 22  
> blocked from the outside world?? Have you tested that? Consider  
> running ssh on an alternate port if running OS X server (as Apple's  
> GUI config tools for the firewall don't always allow you to block  
> port 22).

I do not have port 22 blocked, and I unfortunately need to use it.

> Do consider running your mail services off a machine that is not a  
> Mac OS X server. OS X server is merely OS X client/workstation with  
> a pretty management utility for some 'nix services. It is not  
> stable under high load -- and it is not even stable under moderate  
> load without numerous performance tweaks (it doesn't cope at all  
> well if the disk queue goes up a touch or loadavg is at all  
> interesting - ie it degrades poorly under load).

I'll keep this in mind.

Thanks again,

Alan

-- 
Alan Schmitt <http://alan.petitepomme.net/>

The hacker: someone who figured things out and made something cool  
happen.
.O.
..O
OOO


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