Hello Upendra,
Real-Time apply is always considerable and not going to overhead for the
primary/production database. I hope you are in maximum performance and in
that case primary never cares standby whether the redo is transferred or
written into standby redo log files. I would say must implement.
As Tony said, the redo log size changes not going to impact any way. If for
example you have redo log size of 1GB then to transfer over network it
splits into small chunk of sizes 8192, As per your earlier reply you have
mentioned there is no issue from bandwidth but have you tested the required
bandwidth?
The required bandwidth can be calculated with the predefined formula based
on the generated redo size per second. You can refer below links for more
information.
http://www.oracle.com/au/products/database/maa-wp-10gr2-dataguardnetworkbestpr-134557.pdf
.
Optimizing and Tuning Network -->
http://www.toadworld.com/platforms/oracle/w/wiki/11366.let-s-optimize-data-guard-configuration-ii
by ping or tnsping you may not get always consistent data, i would say
measure the bandwidth speed and optimize the network tuning by larger SDU
size.
Thanks.
On Sat, Jan 9, 2016 at 7:27 PM, Upendra nerilla <nupendra@xxxxxxxxxxx>
wrote:
I just tested using ping. Both sides doesn't show any packet drops. Both
sides show the same latency.
Is there a way to set oradebug event/debug to get additional information
on why the archivelog is being to the other side? How should I troubleshoot
this further?
Real-time apply sounds interesting. I am concerned about adding the
dependency of the DR site to Prod.
-Upendra
------------------------------
Date: Sat, 9 Jan 2016 13:19:57 +1000
From: dedba@xxxxxxxxxx
To: nupendra@xxxxxxxxxxx; nassyambasha@xxxxxxxxx
CC: oracle-l@xxxxxxxxxxxxx
Subject: Re: Troubleshooting log shipping
I agree with Nassyam, the errors clearly point to network problems between
the production and standby sites. I have had the same on various occasions,
especially when production traffic and log shipping used the same network
devices. Congestion can take place on various levels in the OSI layers of
the servers involved, not just the network devices.
The solution is not to increase the file size, as the network traffic on
copy only increases, but enabling real-time apply as suggested. When
real-time apply is enabled, the production log writer will write
transactions to the standby log directly, in tandem with the local redo
log. When the log is archived, a complete copy already exists on the DG
server and no further network copy is needed. In addition, changes are
applied to the standby database as they occur, so activity on that server
is steady and does not rise and fall as would be the case with log
shipping. This does not increase the load on the production server, but you
must take care that the production database will not hang if for any reason
the log writer cannot write to the standby log.
It can also not do any harm to check that the network configuration is
sane, e.g. that a ping between the two servers does not show any lost
packets. Ususally when this happens, a server is set up to use two or more
NICs in tandem (i.e. teamed/bonded/etc.) but the switches they are
connected to are not set up to support this. E.g. with 2 teamed/bonded/..
NICs, you'd see about 50% packet loss if the switches are not configured
correctly.
Cheers,
Tony
On 09/01/16 12:49, Upendra nerilla wrote:
I reviewed the network throughput and we aren't saturated from the network
pipe perspective. We do have riverbed network gear which is compressing and
optimizing the archive transport. I am trying to determine where the
bottleneck is..
Since the logs aren't getting shipped to the DR site, I wanted to get that
resolved.
BTW, I increased redolog size in Prod from 1G to 2G, I still see missing
archivelogs in the DR site.
Real-time apply is not really a requirement, I thought it has more
overhead to the system compared to archive shipping.. With the amount of
data I am pushing, would it help?
I checked the SDU size, we are using the default. How should I determine
if SDU needs to be increased?
I haven't done anything with chunk size, any suggestions on where should I
start?
Thanks
-Upendra
------------------------------
Subject: Re: Troubleshooting log shipping
From: nassyambasha@xxxxxxxxx
Date: Sat, 9 Jan 2016 05:44:08 +0530
CC: oracle-l@xxxxxxxxxxxxx
To: nupendra@xxxxxxxxxxx
Okay this information clears me Data Guard have challenge from network
speed/bandwidth.
One simple question, why not Real-Time Apply ? No need to depend until the
archive log archived and transmitted.
If it is already implemented then, you must consider optimizing the
network by SDU size with large chunk.
Sent from my iPhone
On 08-Jan-2016, at 11:47 PM, Upendra nerilla <nupendra@xxxxxxxxxxx> wrote:
Hi Nassyam et al -
Thanks for your suggestion in setting the archive_dest_state to defer and
enable. That cleared the error. I don't see any errors now.
From looking at the v$archived_log I see that we are behind by a few
hundred logs..
When I check those files with your second query, I do see that a bunch of
archivelogs haven't reached standby.
A couple of followup questions:
1. This is a busy system, redolog size is 1G and in peak we generate about
100-120 logs in an hour. Is it possible that archiver gets too busy and
can't handle this.
Is there a way to determine that? Should I consider increasing the redo
log size to handle this?
2. Does anyone have a script or suggestions on a way to automate copying
the missing archive logs to the Data guard site? Oracle is automatically
pulling these files at the time of logapply. But because of the
latency/throughput between the sites, I would like to copy them ahead of
time so the logapply is going through faster.
Thanks
-Upendra
------------------------------
From: nassyambasha@xxxxxxxxx
Date: Fri, 8 Jan 2016 19:49:33 +0530
Subject: Re: Troubleshooting log shipping
To: nupendra@xxxxxxxxxxx
CC: oracle-l@xxxxxxxxxxxxx
Hello Upendra,
How about the network between primary and standby site? For the best
practice you can do like this to refresh.
Primary> alter system set log_archive_dest_state_3='defer';
Primary> alter system set log_archive_dest_state_3='enable';
Primary> alter system archive log current;
Then check again the above query for the latest errors and also standby
alert log if any sequences are catching up.
From the alert log those errors, i have seen many times the situation can
be vary like network issue or unable to communicate with the background
processes Arch --> (LNS) --> RFS.
Provide the below information first to understand what archive gap you
have.
A) Primary> select thread#,max(sequence#) from v$archived_log group by
thread#;
B) Standby>select thread#,max(sequence#) from v$archived_log where
applied='YES' group by thread#;
If there is any GAP on standby database then we need to check if the
archives whether reached to standby or not.
standby> select thread#,sequence#,name, applied from v$archived_log where
sequence#=&outoutBThread1seq and thread#=1;
standby> select thread#,sequence#,name, applied from v$archived_log where
sequence#=&outoutBThread2seq and thread#=2;
If they are unavailable on standby then we have to check those missing
archives are available on primary using the same above queries. if
available then troubleshooting is required why unable to ship to standby.
If archives unavailable then you know what to do :)
Thanks.
On Fri, Jan 8, 2016 at 7:24 PM, Upendra nerilla <nupendra@xxxxxxxxxxx>
wrote:
oops.. sorry about that.. still waking up.. :)
Here is the output from the second query:
SEVERITY ERROR_CODE timestamp MESSAGE
--------------- ---------- --------------------
----------------------------------------------------------------------
Error 16198 08-JAN-2016 07:23:37 WARN: ARC3: Terminating
pid 18564 hung on an I/O operation
Error 16198 08-JAN-2016 07:23:39 ARC3: Error 16198 due to
hung I/O operation to LOG_ARCHIVE_DEST_3
I see the following alert.log entry in Prod:
Thu Jan 07 19:09:15 2016
LNS: Standby redo logfile selected for thread 1 sequence 435322 for
destination LOG_ARCHIVE_DEST_2
krsv_proc_kill: Killing 1 processes (Process by index)
krsv_proc_kill: Killing 1 processes (Process by index)
ARC1: Error 16198 due to hung I/O operation to LOG_ARCHIVE_DEST_3
ARC1: Detected ARCH process failure
ARC1: Detected ARCH process failure
ARC1: STARTING ARCH PROCESSES
Thanks
-Upendra
------------------------------
From: nassyambasha@xxxxxxxxx
Date: Fri, 8 Jan 2016 18:50:04 +0530
Subject: Re: Troubleshooting log shipping
To: nupendra@xxxxxxxxxxx
CC: oracle-l@xxxxxxxxxxxxx
Hello Upendra,
I understand. But you missed to provide the first query i.e.
set line 120 pages 100
col severity for a15
col message for a70
col timestamp for a20
select severity,error_code,to_char(timestamp,'DD-MON-YYYY HH24:MI:SS')
"timestamp" , message from v$dataguard_status where dest_id=3;
Thanks.
On Fri, Jan 8, 2016 at 6:45 PM, Upendra nerilla <nupendra@xxxxxxxxxxx>
wrote:
Hi Nassyam,
I believe the configuration is correct, otherwise I wouldn't be receiving
any archivelogs at the destination. The DB_unique_name is set to "SID_DR"
in the data guard site and there is a corresponding TNS entry in the PROD
site (with the same name) pointing to the data guard site.
The issue is I am receiving SOME logs but not ALL the archivelogs at the
data guard site.
As I pasted the output of the archivelogs in my earlier message, see the
sequence numbers are all over the place..
This is from ASM:
512 1860501 952576512 954204160 thread_1_seq_*434986*
.5778.900455621
512 1883168 964182016 965738496 thread_1_seq_*434991*
.8962.900456295
512 1850346 947377152 948961280 thread_1_seq_*434997*
.9060.900456899
512 1865067 954914304 956301312 thread_1_seq_*435003*
.3202.900457539
512 134582 68905984 70254592 thread_1_seq_*435008*
.1471.900457605
512 1848325 946342400 947912704 thread_1_seq_*435009*
.3990.900458259
512 1863147 953931264 955252736 thread_1_seq_*435017*
.6484.900458793
512 1834310 939166720 940572672 thread_1_seq_*435023*
.8233.900459079
512 1438234 736375808 738197504 thread_1_seq_*435024*
.11250.900460605
When the logapply hits the point where the archivelog is missing it is
copying from Prod, which is slowing the log apply significantly.
From alert.log at data guard:
Media Recovery Waiting for thread 1 sequence 434987 (in transit)
Here is the output of the query you sent (taken from Prod):
ID STATUS DB_MODE TYPE RECOVERY_MODE
PROTECTION_MODE SRLs ACTIVE
---------- --------- --------------- ---------- -----------------------
-------------------- ---------- ----------
ARCHIVED_SEQ#
-------------
1 VALID OPEN ARCH IDLE
MAXIMUM PERFORMANCE 0 0
355351
2 VALID MOUNTED-STANDBY LGWR MANAGED
MAXIMUM PERFORMANCE 14 3
435651
3 VALID MOUNTED-STANDBY LGWR MANAGED
MAXIMUM PERFORMANCE 14 3
353763
Thanks
-Upendra
------------------------------
From: nassyambasha@xxxxxxxxx
Date: Fri, 8 Jan 2016 15:08:10 +0530
Subject: Re: Troubleshooting log shipping
To: nupendra@xxxxxxxxxxx
CC: oracle-l@xxxxxxxxxxxxx
Hello Upendra,
If the configuration is perfect then the redo/archive should receive on
remote destinations.
If you see below, you have mentioned service=SID_DR, can you confirm you
have used the Oracle net service which points to the related standby
database? and what about db_unique_name also you have mentioned SID_DR, it
should be the unique name but not SID, so it depends on configuration
however what the db_unique_name,sid, service configured.
"*service="SID_DR", LGWR ASYNC NOAFFIRM delay=0 optional
compression=disable max_failure=0 max_connections=1 reopen=15*
* db_unique_name="SID_DR"
net_timeout=30, valid_for=(all_logfiles,primary_role)*"
Can you send output of this below query? Run them from primary.
set line 120 pages 100
col severity for a15
col message for a70
col timestamp for a20
select severity,error_code,to_char(timestamp,'DD-MON-YYYY HH24:MI:SS')
"timestamp" , message from v$dataguard_status where dest_id=3;
select ds.dest_id id
, ad.status
, ds.database_mode db_mode
, ad.archiver type
, ds.recovery_mode
, ds.protection_mode
, ds.standby_logfile_count "SRLs"
, ds.standby_logfile_active active
, ds.archived_seq#
from v$archive_dest_status ds
, v$archive_dest ad
where ds.dest_id = ad.dest_id
and ad.status != 'INACTIVE'
order by
ds.dest_id;
Thanks.
On Fri, Jan 8, 2016 at 1:22 PM, Upendra nerilla <nupendra@xxxxxxxxxxx>
wrote:
Hello everyone -
Happy new year!
Oracle RAC 11.2.0.3
OEL 5.x
I have an environment in which the primary is shipping logs to a local
standby and a remote dataguard database.
What I am seeing is that, somehow not all the archivelogs are being
shipped to the remote site. At the time of log apply these logs are being
transmitted over.
Here is an example on how the redologs appear in the remote site:
512 1860501 952576512 954204160
thread_1_seq_434986.5778.900455621
512 1883168 964182016 965738496
thread_1_seq_434991.8962.900456295
512 1850346 947377152 948961280
thread_1_seq_434997.9060.900456899
512 1865067 954914304 956301312
thread_1_seq_435003.3202.900457539
512 134582 68905984 70254592
thread_1_seq_435008.1471.900457605
512 1848325 946342400 947912704
thread_1_seq_435009.3990.900458259
512 1863147 953931264 955252736
thread_1_seq_435017.6484.900458793
512 1834310 939166720 940572672
thread_1_seq_435023.8233.900459079
512 1438234 736375808 738197504
thread_1_seq_435024.11250.900460605
Similar gaps for thread_2 as well..
Here is the configuration of the log_archive_dest_3 on primary for the
remote site:
*service="SID_DR", LGWR ASYNC NOAFFIRM delay=0 optional
compression=disable max_failure=0 max_connections=1 reopen=15
db_unique_name="SID_DR"
net_timeout=30, valid_for=(all_logfiles,primary_role)*
I do not see any errors for the redo transport in the alert log on the
primary site or on the remote DG site.
Any thoughts on how should I troubleshoot this? Are there any known bugs
around this?
Your help is appreciated.
Thanks
-Upendra
--
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<http://www.amazon.in/Oracle-Guard-11gR2-Administration-Beginners/dp/1849687900>
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