952909 wrote:LNS sends redo information from the primary to standby databases. The mode of information passed on depends on the type of apply that you are using in the parameter "log_archive_dest_n" where n stands for the destination number that is pointing to the standby database service on the primary database initialization parameter file. If you are using Real Time apply, then you would be using the term LGWR in the above mentioned parameter and remember that you require Standby Redo Logs created for the real time to be used.
@ Shivananda Rao
I have some more doubts please clear it ...
As per given link i got ,
Log Network Server (LNS) is reading from the redo buffer in the SGA and passes redo to Oracle Net Services from transmission to a standby database.
I google some link says ,
Sample settings for LGWR and ARCH in init.ora file:
For a no-data-loss environment, the LGWR should be used to transfer redo to the standby site even though
the default process for the log transfer service is ARCH.
It is possible to switch between ARCH and LGWR for the log transfer service using the ALTER SYSTEM statement.
The change will not take effect until a log switch occurs on the primary database.
My ques is <please explain clearly>
1.ARCH , LGWR , NLS all three sends redo from primary to standby ?
2. Only LNS sends redo from primary to standby ?
My ques is <please explain clearly>I hope the link presented in the earlier posts explain more precisely :)
952909 wrote:1. lgwr will not sent redo to standby
@ Shivananda Rao ,
Thanks for all replies. we have big argue on this(in my project ) ..so i need good clarity.
Kindly understand my question. Given link not answed to my specific question.
If i set like this in primary 'init.ora'
by default is ARCH.
At what situvationMy QUESTION IS THIS ONLY >>
1. when lgwr involves to send redo to standby ?
2. when arch involves to send redo to standby ?
3. won't they send any redo to standby except LNS ?
LOG_ARCHIVE_DEST_3=’SERVICE=appsstdby1 LGWR’what it indicates here >>
To trace :-to trace :
SQL>select thread#,sequence#,registrar,dest_id from v$archived_log where dest_id=3;
It is possible to switch between ARCH and LGWR for the log transfer service using the ALTER SYSTEM statement.YES
noexpedite archive mode.
alter system set log_archive_dest_3 = 'service=orcldg arch valid_for=(all_logfiles,primary_role) db_unique_name=orcldg' ;
current logfiles and others logfiles will be used.
alter system set log_archive_dest_3 = 'service=orcldg lgwr valid_for=(all_logfiles,primary_role) db_unique_name=orcldg' ;
Vinod Dhandapani wrote:above statement is MISLEADING!!!...ARCH do send redo data
LGWR and ARCH will never send data to standby redo server they only signal LNS to send the redo data. Transmitting the redo data from one server to another is done by some mechanism like FTP which both LGWR and ARCH cannot handle.
ora_arc1_orcl is arch process connected directly to RFS on the standby....waiting to resolve Archive Log Gaps in either ASYNC or SYNC.
ON standby sql terminal STANDBY_SQL>select process,pid,client_pid from v$managed_standby where process='RFS'; PROCESS PID CLIENT_PID --------- ---------- ---------------------------------------- RFS 11397 10648 RFS 10411 10658 on primary database terminal PRIMARY_SQL>exit Disconnected from Oracle Database 11g Enterprise Edition Release 18.104.22.168.0 - 64bit Production With the Partitioning, OLAP, Data Mining and Real Application Testing options [oracle@red1 ~]$ ps -ef|egrep '10648|10658' oracle 10648 1 0 12:10 ? 00:00:00 ora_arc1_orcl oracle 10658 1 0 12:10 ? 00:00:00 ora_nsa3_orcl oracle 12251 10015 0 12:49 pts/1 00:00:00 egrep 10648|10658
Vinod Dhandapani wrote:that i have mention before "Note that deprecated attributes on the LOG_ARCHIVE_DEST_n init. parameter include ARCH,LGWR...etc for 11g"
Both LGWR and ARCH attributes have been deprecated. The redo shipment is done only by LNS process from Oracle 11g.