solr vs fts

[Maciej Milaszewski IQ PL]

Hi
I have a question about tunning dovecot-2.2.36.x

Mail was stared in storage via nfs in MAILDIR via
/home/us/username at domain.ltd/MAILDIR/
I use additionally local dovecot_indexes via SSD disk
(/var/dovecot_indexes%h)

A few clients have 25K and more e-mail

I thinking about use solr like:
 fts = solr
 fts_solr = debug url=http://IP:8983/solr/ (solr in external machine)

Does it make sense ? use dovecot_indexes and fts ?
What is the difference in performance?