impact of SYS password change to data guard

when SYS password is changed, password file changed accordingly.

If it is not sync to standby site, archived log transfer failed as shown below.

-- at primary site

Wed Aug 20 11:14:24 2014
Archived Log entry 2743 added for thread 1 sequence 5263 ID 0x69704abb dest 1:
Archived Log entry 2744 added for thread 1 sequence 5264 ID 0x69704abb dest 1:
Wed Aug 20 11:14:47 2014
Starting background process SMCO
Wed Aug 20 11:14:47 2014
SMCO started with pid=33, OS id=15785
Wed Aug 20 11:15:44 2014
Error 1017 received logging on to the standby
------------------------------------------------------------
Check that the primary and standby are using a password file
and remote_login_passwordfile is set to SHARED or EXCLUSIVE,
and that the SYS password is same in the password files.
      returning error ORA-16191
------------------------------------------------------------
PING[ARC1]: Heartbeat failed to connect to standby 'dg'. Error is 16191.
Wed Aug 20 11:16:45 2014
Error 1017 received logging on to the standby
------------------------------------------------------------
Check that the primary and standby are using a password file
and remote_login_passwordfile is set to SHARED or EXCLUSIVE,
and that the SYS password is same in the password files.
      returning error ORA-16191
------------------------------------------------------------
PING[ARC1]: Heartbeat failed to connect to standby 'dg'. Error is 16191.
Wed Aug 20 11:16:56 2014
Thread 1 advanced to log sequence 5266 (LGWR switch)
  Current log# 2 seq# 5266 mem# 0: /u01/oradata/DG/redo02.log
Wed Aug 20 11:16:56 2014
Archived Log entry 2745 added for thread 1 sequence 5265 ID 0x69704abb dest 1:
Wed Aug 20 11:16:57 2014
Error 1017 received logging on to the standby
------------------------------------------------------------
Check that the primary and standby are using a password file
and remote_login_passwordfile is set to SHARED or EXCLUSIVE,
and that the SYS password is same in the password files.
      returning error ORA-16191
------------------------------------------------------------
FAL[server, ARC3]: Error 16191 creating remote archivelog file 'dg'
FAL[server, ARC3]: FAL archive failed, see trace file.
ARCH: FAL archive failed. Archiver continuing
ORACLE Instance DGS - Archival Error. Archiver continuing.


--at standby site

ARC8: Becoming the 'no FAL' ARCH
ARC1: Becoming the heartbeat ARCH
ARC1: Becoming the active heartbeat ARCH
Error 1017 received logging on to the standby
------------------------------------------------------------
Check that the primary and standby are using a password file
and remote_login_passwordfile is set to SHARED or EXCLUSIVE,
and that the SYS password is same in the password files.
      returning error ORA-16191
------------------------------------------------------------
FAL[client, ARC9]: Error 16191 connecting to dgs for fetching gap sequence