Re: Load sharing POP/IMAP/smtp
On Thu, 6 Feb 2003 06:28, Lauchlin Wilkinson wrote:
> does anyone have any good links/info on how to set up a
> loadsharing/redunant mail servers (pop, imap, smtp). At the moment I
> have 1 server doing all three jobs but we are soon going to grow out of
> this arrangment andI have not had any experience with setting up such
Load sharing and redundancy are two totally different issues.
If you want redundancy then the best thing to do is get a pair of NFS attached
storage devices running in an an active/standby configuration and have the
SMTP/POP/IMAP servers mounting the storage by NFS and using Maildir storage.
This will cost huge amounts of money.
For load sharing I've got Dell 2650 servers with 2*1.8GHz Xeon CPUs, 4G of
RAM, and 5*72G U160 hard drives (4 in a RAID-5 and a hot-spare) that each run
200,000 email accounts with Qmail for delivery and Courier IMAP and POP
At the front end I have Perdition for directing the POP and IMAP to the right
server based on LDAP data (NB the current version in Unstable still doesn't
work properly for this - the next version should do it). Also I have front
end Qmail servers which direct the mail to the correct back-end server based
For typical ISP use you should be able to handle at least 100,000 users for
SMTP, POP, and IMAP on a single box without any significant problems (and
it'll be much easier than installing Perdition etc). I could setup a single
machine to handle 1,000,000 accounts if required, it would be an expensive
machine, but setting up a number of smaller machines with Perdition etc is
also expensive and has management costs too.
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http://www.coker.com.au/postal/ Postal SMTP/POP benchmark
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