[Ilugc] User Accounts
- From: rajasuperman@xxxxxxxxx (Raja Subramanian)
- Date: Wed May 17 17:44:18 2006
Hi,
On 5/17/06, Bharathi Subramanian <sbharathi@xxxxxxxxxxxxx> wrote:
How the large no . of the number user accounts (like 10,000) are
maintained/handled in the (mail) server? /etc/passwd file will be
used ?
Parsing and lookup of large text files (/etc/passwd and friends) is very
inefficient. *BSD maintains passwd information in a Berkeley hashes
for fast access. OpenLDAP uses bdb or an RDBMS on the back end.
The other option is to run a "blackbox mail server", i.e. one where
you don't want to provide shell access to all email user accounts,
see the Cyrus suite. You don't need to add all users to your mail
server.
Cyrus IMAP requires you to create only a single cyrus unix
account for the daemons, and all mail accounts are internally
managed by cyrus. For authentication, Cyrus uses SASL which
you can plug into PAM, LDAP or other backends.
The MTA will also need to use the same SASL auth for account
information and LMTP for local delivery.
If you are running Debian Sarge, the entire thing is fairly painless
to setup. Contact me if you need the config files.
Cyrus comes with excellent documentation, and is typically well
suited for setting up massive mail servers. Carnegie Mellon Uni
(the creators of Cyrus) host ~35,000 accounts on their servers.
For me, the killer features of Cyrus are:
1. Seive -- a procmail like mail filter engine
2. Squatter -- a text indexing engine that allows you to do *very fast*
searches through your mail boxes. Brings Gmail like functionality
to Thunderbird. Full text searches through my server with ~15GB
mailboxes takes ~10s.
3. Great scalability -- scales within a single box and also in clusters.
- Raja
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