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Are LOB's replciated using HADR ?

P: n/a
I am trying to determine whether LOB's are replciated using HADR. The
following documentation from the on-line manuals
http://publib.boulder.ibm.com/infoce...help/index.jsp suggest that
LOB's are not replicated on HADR:
------------------------------------------------
"Non-replicated operations for high availability disaster recovery:

High availability disaster recovery (HADR) uses database logs to
replicate data to the standby database. Non-logged operations are
allowed on the primary database, but not replicated to the standby
database. Non-replicated operations include, but are not limited to,
the following operations:

- BLOBs and CLOBs are not replicated; however, the space for them will
be allocated on the standby database."
-------------------------------------------------

So I assuming that even LOB's that are logged on the primary server are
not replicated to the backup in HADR? But I assume it also means that
if the LOB data is read only (not updated), then we could store the
data on both servers.

Nov 12 '05 #1
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13 Replies


P: n/a
m0****@yahoo.com wrote:
I am trying to determine whether LOB's are replciated using HADR. The
following documentation from the on-line manuals
http://publib.boulder.ibm.com/infoce...help/index.jsp suggest that
LOB's are not replicated on HADR:
------------------------------------------------ ... - NOT LOGGED BLOBs and CLOBs are not replicated; however, the space for them will
be allocated on the standby database."
-------------------------------------------------

I'm told this doc error will be corrected in the next refresh.

Cheers
Serge

--
Serge Rielau
DB2 SQL Compiler Development
IBM Toronto Lab
Nov 12 '05 #2

P: n/a
Can you tell me specifically what the doc error is?

Does that mean that HADR will replciate LOB's?

Nov 12 '05 #3

P: n/a

The current documentation categorizing LOBs among non-logged items is
incorrect. Some LOBs are logged and some aren't. Logged LOBs are
replicated just fine by HADR, non-logged LOBs are not.

Regards,
- Steve P.
--------------------------
Steve Pearson
DB2 UDB for LUW Development, Portland, OR, USA

Nov 12 '05 #4

P: n/a
"Steve Pearson (news only)" <st*******@my-deja.com> wrote in message
news:11**********************@g49g2000cwa.googlegr oups.com...

The current documentation categorizing LOBs among non-logged items is
incorrect. Some LOBs are logged and some aren't. Logged LOBs are
replicated just fine by HADR, non-logged LOBs are not.

Regards,
- Steve P.
--------------------------
Steve Pearson
DB2 UDB for LUW Development, Portland, OR, USA

The doc does not say that LOB's are not logged. It says they are not
replicated with HADR. The InfoCenter on-line doc says:

"BLOBs and CLOBs are not replicated; however, the space for them will be
allocated on the standby database."

This is the on-line version of the manuals at the IBM website. How come it
has not been updated?
Nov 12 '05 #5

P: n/a
"Steve Pearson (news only)" <st*******@my-deja.com> wrote in message
news:11**********************@g49g2000cwa.googlegr oups.com...

The current documentation categorizing LOBs among non-logged items is
incorrect. Some LOBs are logged and some aren't. Logged LOBs are
replicated just fine by HADR, non-logged LOBs are not.

Regards,
- Steve P.
--------------------------
Steve Pearson
DB2 UDB for LUW Development, Portland, OR, USA


Anyone know if HADR has a problem replicating XML Extender?
Nov 12 '05 #6

P: n/a
Mark A wrote:
"Steve Pearson (news only)" <st*******@my-deja.com> wrote in message
news:11**********************@g49g2000cwa.googlegr oups.com...
The current documentation categorizing LOBs among non-logged items is
incorrect. Some LOBs are logged and some aren't. Logged LOBs are
replicated just fine by HADR, non-logged LOBs are not.

Regards,
- Steve P.
--------------------------
Steve Pearson
DB2 UDB for LUW Development, Portland, OR, USA

Anyone know if HADR has a problem replicating XML Extender?

The XML extender is, at the end of the day, just an application.
It should work.

Cheers
Serge

--
Serge Rielau
DB2 SQL Compiler Development
IBM Toronto Lab
Nov 12 '05 #7

P: n/a
Mark A wrote:
"Steve Pearson (news only)" <st*******@my-deja.com> wrote in message
news:11**********************@g49g2000cwa.googlegr oups.com...
The current documentation categorizing LOBs among non-logged items is
incorrect. Some LOBs are logged and some aren't. Logged LOBs are
replicated just fine by HADR, non-logged LOBs are not.

Regards,
- Steve P.
--------------------------
Steve Pearson
DB2 UDB for LUW Development, Portland, OR, USA


The doc does not say that LOB's are not logged. It says they are not
replicated with HADR. The InfoCenter on-line doc says:

"BLOBs and CLOBs are not replicated; however, the space for them will be
allocated on the standby database."

This is the on-line version of the manuals at the IBM website. How come it
has not been updated?

The doc _implies_ that LOBs are not replicated because they are not logged.
What it should state is that LOBs which have been specified as NOT
LOGGED are not replicated (because they are not logged...)

Cheers
Serge

--
Serge Rielau
DB2 SQL Compiler Development
IBM Toronto Lab
Nov 12 '05 #8

P: n/a
"Serge Rielau" <sr*****@ca.ibm.com> wrote in message
news:3n**********@individual.net...
The doc _implies_ that LOBs are not replicated because they are not
logged.
What it should state is that LOBs which have been specified as NOT LOGGED
are not replicated (because they are not logged...)

Cheers
Serge
--
Serge Rielau
DB2 SQL Compiler Development
IBM Toronto Lab


I will have to respectively disagree. The doc says flat out that "BLOBs and
CLOBs are not replicated" and there is no mention of logging, or not
logging, for the reason they are not replicated.
Nov 12 '05 #9

P: n/a
"Serge Rielau" <sr*****@ca.ibm.com> wrote in message
news:3n**********@individual.net...
The XML extender is, at the end of the day, just an application.
It should work.

Cheers
Serge

--
Serge Rielau
DB2 SQL Compiler Development
IBM Toronto Lab


The reason I asked is that Q-Replication doc states that it will not
replicate the DB2 Extenders. I realize that I am asking about HADR, but I
need to make sure.
Nov 12 '05 #10

P: n/a
Here is the exact quote concerning Q-Replicaiton:

"Q replication and event publishing do not support DB2 Extenders(TM)
for Text, Audio, Video, Image, or other extenders where additional
control files that are associated with the extender's LOB column data
are maintained outside of the database."

Nov 12 '05 #11

P: n/a
Mark A wrote:
I will have to respectively disagree. The doc says flat out that "BLOBs and
CLOBs are not replicated" and there is no mention of logging, or not
logging, for the reason they are not replicated.

That's why wars get started over something as stupid as a few words.
We can both agree to diagree without either being provably wrong. :-)

Cheers
Serge
--
Serge Rielau
DB2 SQL Compiler Development
IBM Toronto Lab
Nov 12 '05 #12

P: n/a
"Serge Rielau" <sr*****@ca.ibm.com> wrote in message
news:3n***********@individual.net...
That's why wars get started over something as stupid as a few words.
We can both agree to diagree without either being provably wrong. :-)

Cheers
Serge
--
Serge Rielau
DB2 SQL Compiler Development
IBM Toronto Lab


I opened a PMR and the IBM support person (who found this thread
interesting) has not found any Doc APAR for this (as some have suggested
exists).

BTW: It was an IGS (IBM) DB2 DBA who first referred me to the doc and told
me that HADR will not work with LOB's, so apparently IBM is confusing its
own employees.

We don't need to start a war over this, we just need to get the people in
charge of writing documentation to do a better job.
Nov 12 '05 #13

P: n/a
Mark A wrote:
We don't need to start a war over this, we just need to get the people in
charge of writing documentation to do a better job.

Agreed and please ping me. :-)

Cheers
Serge
--
Serge Rielau
DB2 SQL Compiler Development
IBM Toronto Lab
Nov 12 '05 #14

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