How to recover the data from Redo Log Group which has not been archived yet I have a normal situation where we have 3 Redo Groups (A,B &amp; C) with 1 member (100 MB) each and database is also in Archive log Mode.

In normal scenarios whenever there is redo log switch, there will be a archive file generated and if we have all backups and archive files we can have our database recover till the point we have archive logs.

My question is - when writing to redo log group C (A &amp; B has been archived already), let say 50 MB is written and database crashes, so definitely C group has not been archived yet.

So is it like, while recovering my database again on a different server, i will be losing 50 MB of data? or my understanding is wrong. 

Is there any way we can also get that 50 MB of data somehow?
If you have access to the logfile in redo group C, and you can copy it to the new server, then you will be able to use it for recovering the database on the new server, so you will not lose the data in it.

If you no longer have access to the redo logfile (because not only the database, but the server or storage also crashed, and you are unable to start/repair them), and all you have is your backup, then yes, you will lose the data created after the last backup.