huge database growth (no replies)

Hello

We have piwik installation for about 2.5 years.

Since we moved to piwik 2.3 (3 months ago), the monthly archive table size grow 30 times (from ~2 GB to ~60 GB) although the number of visit grow just by a bit: From 4.9 million visits, 19 million page views on june
To 5.4 million visits, 21 milion page views page views on september

Is this normal ?
Is 60GB archive table is something we should expect ?

some information about the farm

currently we have ~350 site , some very small with very low traffic and some much bigger

Adding new site to the farm is done every several weeks

some information about the traffic:
we have ~5 million visits last month with ~ 20 million page views
In 2011 7 millions visits, 24 million page views
In 2012 21 million visits, 87 million page views
In 2013 55 million visits, 214 million page views
In 2014(till now) 48 million visits, 182 million page views

We do not delete old report from database but do delete visitor logs after 90 days
current Database size ~200 GB ( sits on MySQL)


Thanks
Arik