WiredTiger is an optional engine. The default engine( the older one) is enhanced to collection level concurrency.
If WT engine is better why they haven't at least made it default ? Is it for backward compatibility ?
If WT engine is better why they haven't at least made it default ? Is it for backward compatibility ?
You can upgrade to the 3.0 binary without needing to migrate data to the new storage engine, which takes time.
It wouldn't make sense from an ops standpoint to make an engine-migration mandatory.