Re: HA Mail Server

Javier,

Thanks for the info. I'd thought of doing exactly what you said, except
if there is still going to be a SPOF then there isn't a point of me
doing it.  for me it's not an issue of sharing load, but having a highly
available mail service.

Thanks

On Fri, 2002-09-20 at 11:53, Javier Gostling wrote:
> On Fri, Sep 20, 2002 at 09:54:42AM -0400, Jeff Bearer wrote:
> 
> > I'm researching setting up a 2 node cluster for providing SMTP/POP3/IMAP
> > services.  I'm currently running a HTTPD cluster so I understand all the
> > details of setting up the fail over etc.
> > 
> > The question I'm wondering about is what methods are the best for doing
> > this and the best way to manage the mail spool files. and whether I'd
> > want to use Fail Over or if I can use a Load Balanced configuration.
> > 
> > This shouldn't be too different than a HA file share, etc. but since
> > I've only dealt with rsyncing infrequently changing files to web
> > servers, this looks like it might be more complicated to maintain data
> > integrity. 
> > 
> > Any tips are appreciated, Thanks
> 
> The following is just my opinion of what would make the most solid setup
> for a HA mail server cluster.
> 
> 1. Get ahold of three boxes. I'll name them mail1, mail2 and spool.
> 2. Spool should have plenty of disk for Mail spool files, as well as the
> Operating system with NFS server capability.
> 3. Mail1 and mail2 just need the OS, NFS client capability and mail software.
> My recomendation here goes to postfix or qmail. Also, make sure that your
> POP and IMAP software have MailDir support.
> 4. Have spool NFS export the mail spool directory.
> 5. Have mail1 and mail2 NFS mount the mail spool share.
> 6. Configure the software in mail1 and mail2 to use the mail spool share to
> store e-mail messages.
> 
> Alternatively, you could use a shared disk device (shared SCSI, Fiber Channel)
> and a shared filesystem like GFS (http://www.sistina.com/products_gfs.htm)
> instead of the spool server.
> 
> This solution has the added benefit of being highly scalable, since you can
> keep adding nodes (mail3, etc) as server load increases. Once your mail spool
> access speed becomes the bottleneck, you can improve performance by several
> means:
> 
> 1. Use a separate network segment to access the mail spool.
> 2. Increase network bandwith using ethernet bonding (etherchannel) or Gigabit
> ethernet.
> 3. Add more spool space on a separate disk device and/or processor.
> 
> I see that there is still a SPOF in these, and that is the mail spool machine,
> but I still haven't figured out a way to overcome that, so any suggestions are
> welcome.
> 
> Cheers,
> -- 
> Javier Gostling
> Ingeniero de Sistemas
> Virtualia S.A.
> [email protected]
> Fono: +56 (2) 202-6264 x 130
> Fax: +56 (2) 342-8763
> 
> Av. Kennedy 5757, of 1502
> Las Condes
> Santiago
> Chile
-- 
Jeff Bearer, RHCE
Webmaster, PittsburghLIVE.com
2002 EPpy Award Winner, Best Newspaper Website