[Dovecot] Expected size of index-files?

[Jan van den Berg]

(Wow you are fast!)

"For webmail type setups indexes help a lot. For Outlook/Thunderbird
they help a lot less." 

Very interesting!

I'm scared to use (index) files that go sort of unnoticed (it's not
calculated in the maildirsize file) and can potentially grow with no
limit. 

But I am also curious what ":INDEX=MEMORY" will do with 100k users. How
much MB RAM will one IMAP session on average take? And will this be
removed from memory (or stay cached) when an IMAP session is closed? 

Cheers,

Jan

-----Oorspronkelijk bericht-----
Van: Timo Sirainen [mailto:tss at iki.fi] 
Verzonden: vrijdag 8 februari 2008 17:33
Aan: Jan van den Berg
CC: Dovecot Mailing List
Onderwerp: Re: [Dovecot] Expected size of index-files?

On Feb 8, 2008, at 6:25 PM, Jan van den Berg wrote:

> That's actually quite a lot.
> Consider you run 100k+ mailboxes (1GB each) and you would move to
> Dovecot this will be a huge chunk out of your storage.
> Is using dovecot index files really that much faster than running
> ":INDEX=MEMORY" ? Where could I find some benchmarks about this?

IMAP benchmarks are difficult to produce because they depend so much  
on what clients are used (and how many clients user is using, and how  
user is using the clients). For webmail type setups indexes help a  
lot. For Outlook/Thunderbird they help a lot less.

> so, on average maybe 20%-30%  of the size of your messages ?

It's actually more to do with the number of messages than the size of  
the messages. dovecot.index.cache file is the largest one and it  
completely depends on what IMAP client is used. It contains only the  
information clients are interested in.