Dovecot and FTS experiment

[Tomasz Nowak]

Hello,

I'm trying to experiment with Dovecot and Solr server.
I have >30k email addresses that I want to index to speed up searching 
and save IOPS on mail servers.
For now - I'm doing some experiments and I'm testing how it is working. 
I'm thinking about adding one additional server with Solr and
configure all mail servers to use that server.

I have some questions.
1. I have 15 mail servers. It will be good If I add new server with Solr 
and use it on all Dovecot servers? Or maybe I should install Solr on all 
mail servers?
2. I notice - I have mail account with 3GB of mail. Index files in mail 
dir has 5MB. After indexing mailbox in Solr - index files has 15MB. What 
changes in those files? FTS indexing adds something to that files - but 
what?
3. If I need to disconnect Dovecot from Solr server - simply Can I 
remove plugin configuration from dovecot.conf and everything would be 
working? Or maybe - I need to remove index files and recreate it? It is 
important for me because if some day I would decide to disconnect FTS 
server - I would have to recreate indexes for >30k mailboxes..
4. What if some day I want to change Solr server to new server with 
empty Solr database? I can simply reindex mailboxes? Or I need to do 
something more?

Thanks!