Currently, on un-subscribing, we save the log as:
"Un-subscribed global user $originalEmail for exceeding Bounce Limit $this->bounceRecordLimit"
Since there has been T99444 where a user was unsubscribed due to the ISP bouncing back emails ( can be soft or hard according to the configuration of its mail server ), we thought about keeping full log of the bounce email too so that we can later analyse which bounce and headers caused for this permanent action.
Considering ~10Kib/boune email, according to @hoo, we should be looking at:
11:27 PM <hoo> We received 204340 bounces during the period we have logs in the table for (90 days?)
11:29 PM <hoo> That would be ~2GiB for all bounces we have right now