[Dovecot] Webmail architecture : questions about cache and storage backend
Hi,
I have some questions about dovecot-2.1 and need some advice about software architecture. My company plans to develop a kind of Document Managing System (DMS) and one of its module is a webmail that is currently in a pre-alpha stage (if you are curious you can have a look here http://kairos.smartmobili.com/ but don't be surprised if it doesn't work and please do not use IE for now). From my personal analysis that I am sure is incomplete we have the following options to handle emails storage and cache:
Do not use a cache and rely on dovecot performance to retrieve email's header in real time. Actually don't know if it's that simple because we might need to have a transformed version of emails to be able to display them more easily in the webmail. In this case this option is not really possible.
Use new dovecot-2.1 imap backend and develop a kind of dummy imap server listening to a custom port and storing emails inside a mongoDB database. Advantage is it allow replication very easily.
Wait for dovecot2.x to implement a NoSQL storage. Will it happen soon ?
If you have other suggestions or ideas I would be happy to hear them.
Vincent R.
On Wed, 2011-09-21 at 14:04 +0200, forumer@smartmobili.com wrote:
- Do not use a cache and rely on dovecot performance to retrieve email's header in real time. Actually don't know if it's that simple because we might need to have a transformed version of emails to be able to display them more easily in the webmail. In this case this option is not really possible.
I'm not really sure what you mean by this. Dovecot can cache individual headers and make fetching them fast.
- Use new dovecot-2.1 imap backend and develop a kind of dummy imap server listening to a custom port and storing emails inside a mongoDB database. Advantage is it allow replication very easily.
I suppose that would be the easiest way to do it currently. But note that you can't get all of Dovecot's features to work through imapc backend. Especially the concept of message and mailbox GUIDs doesn't exist in IMAP protocol (some kind of a new X-DOVECOT extension could be added for those of course).
Also implementing a bug-free IMAP server may not be as easy as you think, even though Dovecot uses only a small subset of IMAP commands. Be sure to stress test Dovecot using imaptest: http://imapwiki.org/ImapTest (I've noticed this week that Exchange totally screws up its internal IMAP state when stress testing.)
- Wait for dovecot2.x to implement a NoSQL storage. Will it happen soon ?
I hope so! :) But I can't really say when.. My priorities currently are:
- Do whatever paying customers want (not that much currently)
- Finish v2.1.0 (still quite a lot of small things to do)
- Create v2.2 branch where lib-storage API is changed to support more asynchronous lookups, and modify imapc backend to use those (= support handling commands in parallel)
- Probably change dbox code to use lib-fs, or maybe create a new backend using lib-fs
- Implement NoSQL backend for lib-fs
Actually 3 isn't really necessary for 4-5, but it improves the performance.
participants (2)
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forumer＠smartmobili.com
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Timo Sirainen