ahmad riza h nst put forth on 11/8/2010 4:08 AM: >> You won't have local system accounts. Just setup Postfix and Dovecot to >> query your current mysql domain and user database. It may take some >> tweaking, but what doesn't? ;) >> > > thanks for your reply stan, > > the problem is we have to use webmin + virtualmin for user interface > (control panel), and it seems virtualmin doesn't support postfix > virtual user via mysql db, indeed they do it alias with unix system > users.
"Have to"? There are alternatives, such as http://www.ispconfig.org/ispconfig-3/ In the absence of Virtualmin support for your mysql user db, how are you going to populate the local UNIX user account database on the new system? Does a tool already exist allowing you to do so? If not, and you will have to write such a tool, I suggest you focus your efforts on writing a tool/plugin to allow Virtualmin to directly read/write your mysql user db. >> Are you using Dovecot for IMAP and POP or just POP? > > IMAP and POP. > >> >>> our hardware is hp dl180 g6 (a xeon quad core + raid 1 + 4G ram) >> >> Ok, that answers one of my previous questions. This system isn't nearly >> strong enough for thousands of users. You should: >> >> 1. Bump the RAM up to at least 8GB >> 2. Install the second matching quad core processor >> > > i understand, but we only use this server for mailboxes only, so there > will be no spamassassin or clamav etc on the server, we have separate > mail filtering (mx) on another servers. As you should. So, can you disable those buttons so your users can't access them? Or will you allow them to press the buttons, but they won't really do anything? The SA config in Virtualmin is per user is it not? > currently we have another mailbox server (it hp dl 180 g6 too) with > qmail and vpopmail, there are about 11 thousands virtual user on the > server and it still running well at this time, thats why we think > postfix and dovecot can do it with same hardware. Ahh, then you're ignorant of IMAP processing and communications patterns. The load generated by IMAP clients versus POP clients cat be well over 100 fold, especially if the clients are not syncing messages locally. Each click on a mail folder or email generates a packet to the IMAP server and a response packet back to the client. Multiply that by 1000 concurrent clients. The communication pattern is more akin to telnet or SSH. POP is more similar to FTP. One is constantly interactive. The other creates a burst as is then done. IMAP generates an order of magnitude more load on a server than POP does. You've apparently not heard of body searches on IMAP mailboxes. Once client can tie up an entire server CPU core for 10-20 seconds at a time searching an IMAP folder containing 5,000-10,000 messages in it. This is probably the heaviest hitting IMAP feature your users could take advantage, although there are others that will suck up server resources. POP has none of these features, so load is directly correlated to the number of concurrent logins and new messages in the queue. There are many more performance variables WRT IMAP servers. > i will read this, thanks. > >> http://wiki2.dovecot.org/LDA >> http://wiki2.dovecot.org/LDA/Postfix >> http://wiki2.dovecot.org/Pigeonhole/Sieve >> http://wiki2.dovecot.org/Pigeonhole/ManageSieve Join the Dovecot mailing list. Post what you're requirements are, how many users you have, what you plan to do, and what hardware you plan to use. Ask for advice on the mysql userdb issue WRT Virtualmin. Ask for opinions on what hardware you need to host 11,000 IMAP users. http://www.dovecot.org/mailinglists.html -- Stan
