Re: Clustering mail servers - Cyrus or Courier ?
Przemyslaw Wegrzyn [EMAIL PROTECTED] writes:
On Mon, 6 Aug 2001, Jeff Waugh wrote:
You ought to check out Scalemail, which is being developed expressly for
this purpose. It is a combination of Courier POP/IMAP and postfix. Very
powerful combo.
Hmmm, I can see it's in early stage of developement.
The only thing really missing is the Courier-IMAP login
mechanism. And I think I got it done, just haven't had time to
plug it in and test it. After that, it's all bug fixes and
refactoring code to be prettier. The thing delivers to
maildirs already.
--
tv@{{hq.yok.utu,havoc,gaeshido}.fi,{debian,wanderer}.org,stonesoft.com}
double a,b=4,c;main(){for(;++a2e6;c-=(b=-b)/a++);printf(%f\n,c);}
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Re: Clustering mail servers - Cyrus or Courier ?
On Sat, 11 Aug 2001, Russell Coker wrote: On Sun, 5 Aug 2001 16:10, Przemyslaw Wegrzyn wrote: I'm looking for good solution for big, scalabale mailserver installation, for 500,000 accounts and more... As for now I think: - sharng NFS-mounted mail storage is not so good idea. Why not? If you use Maildir storage then it's NFS safe. If you use a NetAPP Filer, a VA NAS device (or any machine running 2.2.x kernel with LVM, Ext3, and appropriate NFS kernel-server patches as the VA NAS devices did), or some similarly powerful NFS server then performance should be more than adequate. Hmmm, I'm really afraid about NFS, I've heared that Linux NFS implementation is broken, many times. Can anyone explain it a bit ? For Ext3 you need to keep the number of entries in a directory down to 1000 for best performance, but most users don't have that many messages in their mail folder. So you just have to do suitable directory hashing to make sure you don't have too many users in a directory (all mail storage software has support for this). Yeah, I do such hushing on every bigger mailserver, it's a common solution. Currently I'm testing qmail-ldap + maildrop + Courier-IMAP. Works well, but it's not HA solution :| Then you can have multiple mail servers running at the same time for increased reliability. This is much better than the Perdition approach of increasing the number of points of failure. Having an NFS file server as a single point of failure is as good as it gets, making an NFS file server reliable is much easier than making a mail server reliable... Running multiple mail servers over NFS will actually makie it HA-like system. But is it good solution for high load ? Using perdition-like solution to split mailspool between separate NFS servers, and using multiple mailservers for each NFS backend would probably build good scalable solution. -=Czaj-nick=- -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: Clustering mail servers - Cyrus or Courier ?
On Mon, 6 Aug 2001, Charl Matthee wrote: On Sun, Aug 05, 2001 at 04:10:13PM +0200, Przemyslaw Wegrzyn wrote: I'm looking for good solution for big, scalabale mailserver installation, for 500,000 accounts and more... As for now I think: - sharng NFS-mounted mail storage is not so good idea. - scaling can be done by partitioning mail storage between servers (with a little less avialabilty risk). Sharing over NFS I would not be too spooked about, all depends more on how the NFS shares are mounted, and what directory structure you've chosen. I'm currently testing a new system here, Postfix as SMTP server, and Courier as IMAP/POP server.. Both authenticate and do lookups through MySQL, and accesstimes are quite good. With 100k accounts and about 100 mail in the maildir, login times were about 0.6 secs for pop3/imap. With this setup you also get the benefit of no real user accounts for the email, all is run as one single user/group. Postfix supports several different MySQL servers also, so you can set up replication between a couple of MySQL-servers and then add those to Postfix. Havent checked Couriers support for that though. One important thing, really try to distribute your accounts in a manner so you dont get more than say a thousand accounts in each directory. Ext2 as a filesystem has it's limitations, but I prefer that for now, as I know it's well tested and reliable. For me if I have a user called foobaren and one called fooenbar they go in /var/spool/mail/foo/bar/foobaren/ /var/spool/mail/foo/enb/fooenbar/ The quota is the problem in this setup. Courier supports maildirquota, but not verified yet if Postfix does. Possibly you could solve that by using maildrop as delivery agent. Regards Roger A - Roger Abrahamsson, Sys/Net Admin, Obbit AB Phone: (+46)(0)90 133310Fax:(+46)(0)90 133370 - -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: Clustering mail servers - Cyrus or Courier ?
Hey Przemyslaw, Sunday, August 05, 2001, 10:10:13 AM, you wrote: PW However, AFAIK it can be done only with Cyrus with its IMAP Aggregator, or PW with qmail-ldap + Courier-IMAP... Perdition (http://www.ca.us.vergenet.net/linux/perdition/) should allow you to do the same thing as Cyrus murder, on other mail systems. -- Kevin -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: Clustering mail servers - Cyrus or Courier ?
On Mon, 6 Aug 2001, Jeff Waugh wrote: quote who=Przemyslaw Wegrzyn However, AFAIK it can be done only with Cyrus with its IMAP Aggregator, or with qmail-ldap + Courier-IMAP... You ought to check out Scalemail, which is being developed expressly for this purpose. It is a combination of Courier POP/IMAP and postfix. Very powerful combo. Hmmm, I can see it's in early stage of developement. Does postfix support ldap nativly ? -=Czaj-nick=- -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: Clustering mail servers - Cyrus or Courier ?
On Mon, 6 Aug 2001, Charl Matthee wrote: If you are willing to spend the money I can recommend you use CommuniGate Pro (Stalker Software, www.stalker.com). It is a fast and very scalable mail server (It does SMTP, POP3, IMAP, etc.). We run a free webmail sevice and our original application was homegrown. We ran into some scalability issues (becuase the software was never meant to cope with 10+ users). CommuniGate Pro is the answer for us. Yeah, I've looked at their web page, software looks well. Can you tell anything about its design ? -=Czaj-nick=- -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: Clustering mail servers - Cyrus or Courier ?
quote who=Przemyslaw Wegrzyn LMTP would be the best if talking about Cyrus). It should support LDAP database. Postfix supports both of these. It is an *awesome* MTA. - Jeff -- I must be getting old... Buying toothpaste with gel in it is no longer an Absolute Necessity. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: Clustering mail servers - Cyrus or Courier ?
On Tue, 7 Aug 2001, Jeff Waugh wrote: quote who=Przemyslaw Wegrzyn LMTP would be the best if talking about Cyrus). It should support LDAP database. Postfix supports both of these. It is an *awesome* MTA. You've surprised me a little. I was always thinking postfix is just another MTA, nothing more... -=Czaj-nick=- -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
