DataGuard

Hi,

We are in the process of implementing Standby DB (Physical). We are running our production db in oracle9i RAC with two instances(in IBM AIX5.2 with HACMP 5.2 Cluster). We would like to send the archived redo log files from Primary DB to StandbyDB with time frequency rather than sending the archivelog files to standby destination as and when it got generated.

For doing the above, is there any utility / unix scripts to compress and send the archive log files to the standby destination with defined time frequency....if any such utility/scripts available it will be very useful for us.....


thanks....in advance...

ramesh

Hi,
You can delay the application of archived redo logs on the standby by the command

Code:

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ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DELAY ;

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And to return it to default mode ie no delay,

Code:

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ALTER DATABASE RECOVER MANAGED STANDBY DATABASE NODELAY;

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Quote:

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Originally posted by ramesh_v
Hi,

We are in the process of implementing Standby DB (Physical). We are running our production db in oracle9i RAC with two instances(in IBM AIX5.2 with HACMP 5.2 Cluster). We would like to send the archived redo log files from Primary DB to StandbyDB with time frequency rather than sending the archivelog files to standby destination as and when it got generated.

For doing the above, is there any utility / unix scripts to compress and send the archive log files to the standby destination with defined time frequency....if any such utility/scripts available it will be very useful for us.....


thanks....in advance...

ramesh

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I'm confused....if you have RAC why do you want to do standby as well?

Quote:

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I'm confused....if you have RAC why do you want to do standby as well?

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I did think about that aswell. Is there any particular reason why you would want to do that?

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Originally posted by OracleDoc
I'm confused....if you have RAC why do you want to do standby as well?

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RAC = high availability
Standby = disaster recovery

In RAC environment, in most cases all the nodes of the cluster are located in the same geographical location, usualy in the same building/room. So for example if the ceiling of that building colapses, probably all the nodes of the RAC will be damaged. So what good does it do that you had RAC? That is why it is not unusual to have a standby database on some distant location that covers you in the events of such "environmental disasters".

Quote:

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Originally posted by jmodic
RAC = high availability
Standby = disaster recovery

In RAC environment, in most cases all the nodes of the cluster are located in the same geographical location, usualy in the same building/room. So for example if the ceiling of that building colapses, probably all the nodes of the RAC will be damaged. So what good does it do that you had RAC? That is why it is not unusual to have a standby database on some distant location that covers you in the events of such "environmental disasters".

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you could also have a local standby in case you need to do PIT recovery quickly - ergo a time delay

Or have a read-only version of the database used for reporting purposes.

Set ARCHIVE_LAG_TARGET to an integer value.
If you set it to 0 (zero) then it is disabled. One can alter the value by ALTER SYSTEM...


ARCHIVE_LAG_TARGET limits the amount of data that can be lost and effectively increases the availability of the standby database by forcing a log switch after the specified amount of time elapses.

A 0 value disables the time-based thread advance feature; otherwise, the value represents the number of seconds. Values larger than 7200 seconds are not of much use in maintaining a reasonable lag in the standby database. The typical, or recommended value is 1800 (30 minutes). Extremely low values can result in frequent log switches,
which could degrade performance; such values can also make the archiver process too busy to archive the continuously generated logs.

Thanks,

Thanks....

Actually we are planning to implement DR Site with physical standby DB (both primary and standby will run in Oracle9i RAC). Our DB size is around 350gb, and the redo generation is around 30gb per day.
Sending the archivelog files in online requires more mbps leased lines, instead of that we and to compress the archivelog file in the primar site itself and sending to DR site in specific interval of time (once in 30min or 1hr). For this we need some kind of a deamon program running in both primary and DR site which will send and received the compressed archivedlog file and uncompress it and putting it in the actual archivelog folder of the DR site.

Please suggest some kind of utility for this.......

thanks

Quote:

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Originally posted by ramesh_v
Thanks....

Actually we are planning to implement DR Site with physical standby DB (both primary and standby will run in Oracle9i RAC). Our DB size is around 350gb, and the redo generation is around 30gb per day.
Sending the archivelog files in online requires more mbps leased lines, instead of that we and to compress the archivelog file in the primar site itself and sending to DR site in specific interval of time (once in 30min or 1hr). For this we need some kind of a deamon program running in both primary and DR site which will send and received the compressed archivedlog file and uncompress it and putting it in the actual archivelog folder of the DR site.

Please suggest some kind of utility for this.......

thanks

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won't you defeat the automatic gap resolution process by doing this?

From what I've read, data guard (max performance mode) supports ssh port forwarding with data compression. I've never used it myself. But articles talk about having reduced n/w traffic by 50% (and a slight cpu overhead).

Check out http://www.oracle.com/technology/dep...etBestPrac.pdf

Quote:

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Originally posted by Axr2
From what I've read, data guard (max performance mode) supports ssh port forwarding with data compression. I've never used it myself. But articles talk about having reduced n/w traffic by 50% (and a slight cpu overhead).

Check out http://www.oracle.com/technology/dep...etBestPrac.pdf

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thanks for sharing that doc

steve

RAC = protection from instance failure

DataGuard = protection from media failure