Simple "Oracle Database" hack in python to change the size of the redo logs files. It assumes that Oracle Managed Files are being used.

ChangeRedoSize.py

import argparse
import time

import cx_Oracle
from prettytable import PrettyTable


class RedoLogManager():

    def get_log_files_info(self, cursor):
        cursor.execute('''SELECT group#, thread#, sequence#, bytes/(1024*1024), members, status FROM sys.v_$log''')
        result = cursor.fetchall()
        logs = []
        for row in result:
            logs.append(row)
        return logs

    def get_standby_log_files_info(self, cursor):
        cursor.execute('''SELECT group#, thread#, sequence#, bytes/(1024*1024), status FROM sys.v_$standby_log''')
        result = cursor.fetchall()
        logs = []
        for row in result:
            logs.append(row)
        return logs

    def print_log_info(self, logs):
        table = PrettyTable(["Group No.", "Thread No.", "Sequence No.", "Size (MB)", "No of Members", "Status"])
        for row in logs:
            table.add_row(row)
        print table

    def print_standby_log_info(self, logs):
        table = PrettyTable(["Group No.", "Thread No.", "Sequence No.", "Size (MB)", "Status"])
        for row in logs:
            table.add_row(row)
        print table

    def display_log_info(self, username, password, connectstring):
        with cx_Oracle.connect(username, password, connectstring, mode=cx_Oracle.SYSDBA) as connection:
            cursor = connection.cursor()
            print ("Current Redo Log configuration")
            logs = self.get_log_files_info(cursor)
            self.print_log_info(logs)
            logs = self.get_standby_log_files_info(cursor)
            if len(logs) != 0:
                print('Standby Logs')
                self.print_standby_log_info(logs)

    def create_standby_logs(self, username, password, connectstring):
        sb_log_statement = "alter database add standby logfile size {}M"
        with cx_Oracle.connect(username, password, connectstring, mode=cx_Oracle.SYSDBA) as connection:
            cursor = connection.cursor()
            logs = self.get_log_files_info(cursor)
            log_size = max((map(lambda x: x[3], logs)))
            for i in range(0, len(logs) + 1):
                cursor.execute(sb_log_statement.format(log_size))
            print("Created standby log files")
            logs = self.get_standby_log_files_info(cursor)
            self.print_standby_log_info(logs)

    def change_redo_log_size(self, username, password, connectstring, size):
        switch_statement = "alter system switch logfile"
        drop_statement = "alter database drop logfile group {}"
        create_statement = "alter database add logfile group {} size {}M"

        # target_size = args.size*1024*1024
        target_size = size
        with cx_Oracle.connect(username, password, connectstring, mode=cx_Oracle.SYSDBA) as connection:
            cursor = connection.cursor()
            print ("Current Redo Log configuration")
            logs = self.get_log_files_info(cursor)
            self.print_log_info(logs)
            # number_of_log_groups = len(logs)
            while True:
                print(switch_statement)
                cursor.execute(switch_statement)
                logs = self.get_log_files_info(cursor)
                incorrectly_sizes_logs = [row for row in logs if row[3] != target_size]
                if len(incorrectly_sizes_logs) == 0:
                    print("All logs correctly sized. Finishing...")
                    break
                inactive_rows = [row for row in logs if row[5] == 'INACTIVE' and row[3] != target_size]
                if len(inactive_rows) > 0:
                    print(drop_statement.format(inactive_rows[0][0]))
                    cursor.execute(drop_statement.format(inactive_rows[0][0]))
                    print(create_statement.format(inactive_rows[0][0], target_size))
                    cursor.execute(create_statement.format(inactive_rows[0][0], target_size))
                    logs = self.get_log_files_info(cursor)
                    time.sleep(1)
            print ("New Redo Log configuration")
            logs = self.get_log_files_info(cursor)
            self.print_log_info(logs)


if __name__ == '__main__':

    parser = argparse.ArgumentParser(description='Adjust the size of all redo logs')
    group = parser.add_mutually_exclusive_group(required=False)
    parser.add_argument('-u', '--user', help='sys username', required=True)
    parser.add_argument('-p', '--password', help='sys password', required=True)
    parser.add_argument('-cs', r'--connect_string', help='connect string to database (container)', required=True)
    group.add_argument('-s', '--size', help='new size of the redo logs (MB)', required=False, type=int)
    group.add_argument('-d', '--display', help='just display the current size of the redo logs (MB)', dest='display_only', action='store_true', required=False)
    group.add_argument('-sb', '--standby', help='create standby logs', dest='create_sb_logs', action='store_true', required=False)
    args = parser.parse_args()

    rlm = RedoLogManager()

    if args.display_only:
        rlm.display_log_info(args.user, args.password, args.connect_string)
    elif args.create_sb_logs:
        rlm.create_standby_logs(args.user, args.password, args.connect_string)
    else:
        rlm.change_redo_log_size(args.user, args.password, args.connect_string, args.size)

A simple python script to change the size of the redo logs for an Oracle Database. This isn't designed to work against a RAC cluster but could be changed to do so. It also depends on the use of Oracle Managed Files. Again this could be trivially changed as well...