Thanks folks for your precious advise.

I have increased the size of Redo logs from 50M to 100M. Now, I am monitoring it.

But, now how can I change the group numbers and name of new log files.

Earliler, there were 3 groups 1,2 and 3 with 2 members each such as log1.dbf, log1a.dbf, log2.dbf, log2a.dbf, log3.dbf, log3a.dbf.

I have dropped old groups and their members, files.

Now, group numbers are 4,5 and 6 and new redo log file names are log4.dbf, log4a.dbf, log5.dbf, log5a.dbf, log6.dbf, log6a.dbf.

How can I restore old group numbers and old log file names?

Thanks,