{9i New Features: DataGuard}
Next installment of 9i new features, like always send hate mail to /dev/null. Also if I've lied in something feel free to correct/flame me for it. The Saga continues: Oracle 9i New Features: 9i Data Guard So you have Oracle 8i standby database, what is new with 9i standby also known as Data Guard. Well in theory it can be totally automated. In 8i you had to put the database in managed recovery mode(or you manually did recovery) on the standby db. I hope no one was doing manual recovery every time a archive log was shipped across. :) Now with 9i dataguard, the standby database can be built either: 1. manually just like you did in 8i or2. automagically with OEM Dataguard Wizard(crazy wizards foreverything anymore). I personally couldnt get the wizard to work with 9.0.1.0. Does it work now?, I'm not sure as I've not tested it as of recent. The manual method works just fine. Ok so you need to create a standby database, we're not going to cover that here, why?, Mostly cause we're only going to cover the new aspects, you all can read the docs as well as I can to build the db. On to the new stuff: Your standby database in 8i was only in what we call "delayed" protection mode, which means there is a delay from the time the logs are completed on the primary database before they are appliedto the standby database. Now with 9i, you have 3 other modes: Guaranteed protection: indicates that primary database modifications are available to the standby database, up to the last committed transaction. The standby database cannot diverge from the primary database at all, and no data can be lost. If a standby database is unavailable, processing automatically halts on the primary database as well. Instant Protection: With instant protection, the standby database may temporarily diverge from the primary database, but upon failover to the standby database, the databases can be synchronized, and no data will be lost. Rapid Protection: With rapid protection, the log writer process transmits redo logs to the standby sites. Use this mode when availability and performance on the primary database are more important than the risk of losing a small amount of data. An important note is that in Guaranteed and Instant protection mode that the logs are written in SYNCHRONOUS mode to the standby site. Rapid and Delayed mode are ASYNC writes. So this begs to ask what is the difference between Guaranteed and Instant? Well in Guaranteed mode the logs are applied and there is no data divergence from the primary and standby db. Whereas Instant mode there can be data divergence but upon failover there will beNO data loss. So since we wont have data loss, there is a new way to "failover" to a standby database, called switchover. You can literally be able to switch to a standby database and switchback to the original primary WITHOUT having to reinstantiate(ie: rebuild) the primary. A very nice feature, this gives you the capability to do rolling upgrade of OS -NOTICE, NOT ORACLE BINARIES YET, ONLY THE OS. In 8i you could only do a failover(which required rebuilding the primary), you can still do a failover in 9i if you've lost the primary db in some disaster like the computer room caught on fire. Now for the automated part: There is the dataguard manager/broker, it can be run from command line($ORACLE_HOME/bin/dgmgrl) as well as from OEM. This gives you the luxury of oracle doing all the work to maintain consistency between the primary and standby database. Way too much to cover here but it handles automatically applying logs, notification of down standby, etc. Feel free to ask anything about Dataguard to me directly at [EMAIL PROTECTED] Joe
RE: {9i New Features: DataGuard}
I have been working on this dataguard on 8I
in this u can switch over the production to standby as production and switch
back to orignal production
by making the switch over production to
standby again.
The 9i OEM dataguard does not support 8I it
only supports 9i
so the only option is to run from command
line.
It is working fine as such i have not faced
any probs from that.
-Original Message-From: JOE TESTA
[mailto:[EMAIL PROTECTED]]Sent: Thursday, April 25, 2002 1:14
PMTo: Multiple recipients of list ORACLE-LSubject: {9i
New Features: DataGuard}
Next installment of 9i new features, like always send hate mail to
/dev/null. Also if I've lied in something feel free to correct/flame me
for it.
The Saga continues:
Oracle 9i New Features: 9i Data Guard
So you have Oracle 8i standby database, what is new with 9i standby
also known as Data Guard.
Well in theory it can be totally automated. In 8i you had to put
the database in managed recovery mode(or you manually did recovery) on the
standby db. I hope no one was doing manual recovery every time a archive
log was shipped across. :)
Now with 9i dataguard, the standby database can be built either:
1. manually just like you did in 8i or2. automagically
with OEM Dataguard Wizard(crazy wizards foreverything anymore).
I personally couldnt get the wizard to work with 9.0.1.0. Does it
work now?, I'm not sure as I've not tested it as of recent. The manual
method works just fine.
Ok so you need to create a standby database, we're not going to cover
that here, why?, Mostly cause we're only going to cover the new aspects, you
all can read the docs as well as I can to build the db.
On to the new stuff:
Your standby database in 8i was only in what we call "delayed" protection
mode, which means there is a delay from the time the logs are completed on the
primary database before they are appliedto the standby database. Now
with 9i, you have 3 other modes:
Guaranteed protection: indicates that primary database modifications are
available to the standby database, up to the last committed transaction.
The standby database cannot diverge from the primary database at all, and no
data can be lost. If a standby database is unavailable, processing
automatically halts on the primary database as well.
Instant Protection: With instant protection, the standby database may
temporarily diverge from the primary database, but upon failover to the
standby database, the databases can be synchronized, and no data will be
lost.
Rapid Protection: With rapid protection, the log writer process transmits
redo logs to the standby sites. Use this mode when availability and
performance on the primary database are more important than the risk of losing
a small amount of data.
An important note is that in Guaranteed and Instant protection mode that
the logs are written in SYNCHRONOUS mode to the standby site. Rapid and
Delayed mode are ASYNC writes.
So this begs to ask what is the difference between Guaranteed and
Instant? Well in Guaranteed mode the logs are applied and there is no
data divergence from the primary and standby db. Whereas Instant mode
there can be data divergence but upon failover there will beNO data
loss.
So since we wont have data loss, there is a new way to "failover" to a
standby database, called switchover.
You can literally be able to switch to a standby database and switchback
to the original primary WITHOUT having to reinstantiate(ie: rebuild) the
primary.
A very nice feature, this gives you the capability to do rolling upgrade
of OS -NOTICE, NOT ORACLE BINARIES YET, ONLY THE OS.
In 8i you could only do a failover(which required rebuilding the
primary), you can still do a failover in 9i if you've lost the primary db in
some disaster like the computer room caught on fire.
Now for the automated part:
There is the dataguard manager/broker, it can be run from command
line($ORACLE_HOME/bin/dgmgrl) as well as from OEM. This gives you the
luxury of oracle doing all the work to maintain consistency between the
primary and standby database. Way too much to cover here but it handles
automatically applying logs, notification of down standby, etc.
Feel free to ask anything about Dataguard to me directly at [EMAIL PROTECTED]
Joe
RE: {9i New Features: DataGuard}
It even adds the datafile on the standby
database for u, only u have set it in the parameter file of the
dataguard.
-Original Message-From: JOE TESTA
[mailto:[EMAIL PROTECTED]]Sent: Thursday, April 25, 2002 1:14
PMTo: Multiple recipients of list ORACLE-LSubject: {9i
New Features: DataGuard}
Next installment of 9i new features, like always send hate mail to
/dev/null. Also if I've lied in something feel free to correct/flame me
for it.
The Saga continues:
Oracle 9i New Features: 9i Data Guard
So you have Oracle 8i standby database, what is new with 9i standby
also known as Data Guard.
Well in theory it can be totally automated. In 8i you had to put
the database in managed recovery mode(or you manually did recovery) on the
standby db. I hope no one was doing manual recovery every time a archive
log was shipped across. :)
Now with 9i dataguard, the standby database can be built either:
1. manually just like you did in 8i or2. automagically
with OEM Dataguard Wizard(crazy wizards foreverything anymore).
I personally couldnt get the wizard to work with 9.0.1.0. Does it
work now?, I'm not sure as I've not tested it as of recent. The manual
method works just fine.
Ok so you need to create a standby database, we're not going to cover
that here, why?, Mostly cause we're only going to cover the new aspects, you
all can read the docs as well as I can to build the db.
On to the new stuff:
Your standby database in 8i was only in what we call "delayed" protection
mode, which means there is a delay from the time the logs are completed on the
primary database before they are appliedto the standby database. Now
with 9i, you have 3 other modes:
Guaranteed protection: indicates that primary database modifications are
available to the standby database, up to the last committed transaction.
The standby database cannot diverge from the primary database at all, and no
data can be lost. If a standby database is unavailable, processing
automatically halts on the primary database as well.
Instant Protection: With instant protection, the standby database may
temporarily diverge from the primary database, but upon failover to the
standby database, the databases can be synchronized, and no data will be
lost.
Rapid Protection: With rapid protection, the log writer process transmits
redo logs to the standby sites. Use this mode when availability and
performance on the primary database are more important than the risk of losing
a small amount of data.
An important note is that in Guaranteed and Instant protection mode that
the logs are written in SYNCHRONOUS mode to the standby site. Rapid and
Delayed mode are ASYNC writes.
So this begs to ask what is the difference between Guaranteed and
Instant? Well in Guaranteed mode the logs are applied and there is no
data divergence from the primary and standby db. Whereas Instant mode
there can be data divergence but upon failover there will beNO data
loss.
So since we wont have data loss, there is a new way to "failover" to a
standby database, called switchover.
You can literally be able to switch to a standby database and switchback
to the original primary WITHOUT having to reinstantiate(ie: rebuild) the
primary.
A very nice feature, this gives you the capability to do rolling upgrade
of OS -NOTICE, NOT ORACLE BINARIES YET, ONLY THE OS.
In 8i you could only do a failover(which required rebuilding the
primary), you can still do a failover in 9i if you've lost the primary db in
some disaster like the computer room caught on fire.
Now for the automated part:
There is the dataguard manager/broker, it can be run from command
line($ORACLE_HOME/bin/dgmgrl) as well as from OEM. This gives you the
luxury of oracle doing all the work to maintain consistency between the
primary and standby database. Way too much to cover here but it handles
automatically applying logs, notification of down standby, etc.
Feel free to ask anything about Dataguard to me directly at [EMAIL PROTECTED]
Joe
