[imp] setting newmail checking default.

[Robert Sand]

Thanks,

We already had most of these suggestions in place but some we didn't and 
we are running ok right now.  We will look into imap proxy and I am 
gogin to contact Zend again to see if I can get the accellerator working 
this time.

Lord Apollyon wrote:

>>we are having a problem with our imap servers getting swamped by our imp
>>
>>server.  I'd like to set the newmail checking to every 5 minutes by 
>>default.  Is there a way to do this? 
>>    
>>
>
>You can change your site code to do this.  Of course, you probably cannot
>(safely) disable "manual" mailbox reloads/refreshes.
>
>I suspect you'd do well to use an IMAP proxy - that would save you alot of
>connection tear-down and tear-up costs.  Also, do *NOT* use tcp wrappers,
>but rather, employ firewalling settings to limit inbound imap connection
>access (if you use such access limiters at all). tcpd adds some non-trivial
>overheads which become significant at your loadings.
>
>Also, have you changed your inetd.conf settings for the imapd service to
>handle the connection loads?  Stock inetd.conf settings assume a 256
>connection/minute level before backing off new connections as a "flood"
>control measure.  You can change this by appending ".512" or whatever
>connection/minute level you wish to support after the "nowait" parametre.
>
>Your line would look like this (assuming your path to imapd is
>/usr/sbin/imapd) and that you wanted to lift the connection/minute limit to 512:
>
>imap2   stream  tcp     nowait.512  root    /usr/sbin/imapd  imapd
>
>Other tips:
>
>1) *DO* run PHP-Accelerator - the performance delta for me was 4-5X.
>
>2) Look into experimenting with the preemptible-kernel patch which has been
>rock-solid stable for over a year now.
>
>ftp://ftp.kernel.org/pub/linux/kernel/people/rml/preempt-kernel/v2.4/
>
>I use it on most of my servers because even when the loads get high, the
>responsiveness to network and system events smoothly "degenerates" rather
>than getting burpy/laggy (this is alot more noticeable with SSH sessions
>mind you).  Maybe my overall system throughput is slightly less as a result
>(OS theory would tell you this), but all of my users FEEL like the system is
>more responsive.   I will leave you to judge which is the more important.
>
>3) At your loading levels, investigate one of the two imap-proxies - it WILL
>make a difference to not have to re-authenticate and rescan mailbox files.
>
>  
>
>>the Zend php accellerator at this time but may. 
>>    
>>
>
>Get it.  It will both reduce your system loadings and improve page render
>speeds.
>
>Also, try to spray your mailbox spool files across multiple spindles.  All
>of the OS tricks and CPU speeds in the world won't get you far if you're
>bottlenecking at a single hard disk.
>
>All of the ancient mainframe tuning tricks apply to these "modern OSs", folks.
>
>=Apollyon=
>
>  
>

-- 
Robert Sand.
mailto:rsand at d.umn.edu
University of Minnesota, Duluth
Information Technology Systems and Services
144 MWAH
218-726-6122        fax 218-726-7674

"Walk behind me I may not lead, Walk in front of me I may not follow,
 Walk beside me and we walk together"  UTE Tribal proverb.