1) All fully assembled OpenSprinkler units come with a 128MB microSD card. While this is not very large, each log file on average is just a couple kilo-bytes at most. So 128MB means you can store somewhere around 60,000 days of record, and that’s more than 100 years.
As more files are stored, it may increase the computation time to query each file. So far I don’t think there is any obvious slow down on my unit.
2) There is a search function in the forum. You have to go to the top level (opensprinkler.com/forums) and you should see the search button.
3) Regarding marking a thread as solved, there is probably a way. I will let Samer chime in to see if he has any suggestions.