Re: how to build cascaded logical standby from a logical standby
- From: "Eagle Fan" <eagle.f@xxxxxxxxx>
- To: "John Hallas" <john.hallas@xxxxxxxxxx>
- Date: Thu, 24 Apr 2008 19:58:12 +0800
Thanks Hallas.
I didn't find much information in oracle documnet about cascaded logical
standby.
From the following words, looks like it's supported.
*You can configure cascaded Logical Standby database , but, the Redo is
applied from the first Logical Standby which was created
from the PRIMARY.
Because redo data cascaded from a logical standby database is not identical
to the redo data originally generated by the primary database, it ca
nnot be applied to any standby database created directly from the primary
databa
se. Instead, any standby databases that receive cascaded redo data from a
logica
l standby database must be created from a copy of the logical standby
database,
and the following will be true:
Physical standby databases created from a logical standby database will be a
block-for-block copy of the logical standby databa
se and a logical copy of the original primary database.
Logical standby databases created from a logical standby database will be
logical copies of the parent
logical standby database and might bear only a partial resemblance to the
origin
al primary database. This is because the original primary database's data is
the
re and so is anything else stored in the parent logical standby database
includi
ng any other changes such as different indexes or materialized views.
For standby databases that receive cascaded redo data from a logical standby
database, you
must perform the same setup tasks as for a physical or logical standby
database
that receives redo data directly from the primary database. You can use any
tra
nsport mode (LGWR or ARCH) and network protocol (SYNC or ASYNC). If you use
the
LGWR transport mode, you can optionally use standby redo log files on your
stand
by databases.*
On Thu, Apr 24, 2008 at 7:25 PM, John Hallas <john.hallas@xxxxxxxxxx> wrote:
> This relates to a question I was asking a couple of weeks ago about
> Streams from a standby database.
>
>
>
> I was under the impression that you could not run a standby (or Streams)
> from another standby database. I do not know this for certain and logically
> it seems to be a sound idea but I have not seen anything that suggests it
> can be done.
>
>
> ------------------------------
>
> *From:* oracle-l-bounce@xxxxxxxxxxxxx [mailto:
> oracle-l-bounce@xxxxxxxxxxxxx] *On Behalf Of *Eagle Fan
> *Sent:* 24 April 2008 12:00
> *To:* oracle-l
> *Subject:* Re: how to build cascaded logical standby from a logical
> standby
>
>
>
> The oracle database version is 10.2.0.3.
>
> On Thu, Apr 24, 2008 at 6:58 PM, Eagle Fan <eagle.f@xxxxxxxxx> wrote:
>
> Hi All:
>
> I'm trying to build a cascaded logical standby using logical standby as
> intermedial server.
>
> The redo route is like this:
>
> Primary (server A) -> logical standby (server B) -> cascaded logical
> standby (server C).
>
> Server B was copied from Server A and has already been activated as
> logical standby. It's working very well.
>
> Then I copied server C from server B and tried to setup a cascaded logical
> standby.
>
> But when I started logical standby apply on Server C, it was looking for
> archive logs from server A, not Server B.
>
> I was trying to register archive logs from Server B, but got the following
> error:
>
> *SQL> alter database register logfile
> '/oracle/TENG/data01/XFAN10g/archive2/XFAN10g_74.1_652661119_arc';*
>
> *alter database register logfile
> '/oracle/TENG/data01/XFAN10g/archive2/XFAN10g_74.1_652661119_arc'*
>
> ***
>
> *ERROR at line 1:*
>
> *ORA-01324: cannot add file due to DB_ID mismatch*
>
> In DBA_LOGSTDBY_LOG, the archive log is from primary (Server A).
>
> I didn't find detailed action plan of building cascaded logical standby,
> if you have such kind of doc, please give me a copy:)
>
> Any comments or suggestions are appreciated.
>
> Thanks.
>
> --
> Eagle Fan
>
> Sr. DBA
>
>
>
>
> --
> Eagle Fan
>
> Sr. DBA
>
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--
Eagle Fan
Sr. DBA
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