RE: options for read only mirror with 10g SE or SE One
- From: "Mark W. Farnham" <mwf@xxxxxxxx>
- To: oracle-l@xxxxxxxxxxxxx
- Date: Tue, 28 Sep 2004 09:50:50 -0400
Manual standby has worked just fine since at least 6.0.36. (Earlier than
about then certain race conditions on SMP systems could leave you with
corrupt redo logs and no documented way to verify them to know that you
should reinstantiate.) Oracle made it into a product much later after they
figured that out, along with the complications that homegrown solutions
required such as being very careful about adding files and new tablespaces
and issues such as whether to allow unlogged actions (which were not an
issue in 6.0.36, anyway.)
When Oracle indicated that they did not "support" standby databases at those
earlier versions, it was indeed pointed out nearly immediately that a
standby configuration was nothing more nor less than a recovery, and the
question was asked whether Oracle was de-supporting recovery from hot
backups.
Clarification was made that getting individual manual standby strategies
correct was not generally supported, and support did not cover getting free
consulting in this regard, but physical recovery was most certainly NOT
desupported. License issues regarding the recovery machine were not
generally addressed until much later, probably when standby recovery became
an official feature with more robust built in support for keeping it
"right."
I'm not sure who did it "first." I do remember hearing "but you're only
allowed to do that with support from Oracle Consulting" some number of years
after I had considered it a routine way to support rapid recovery and the
creation of databases (cancel recovery, copy, startup with rename open
resetlogs) as a convenient frozen image for decision support and loading
time series information into long term data stores (warehouses, marts,
etc.).
At this writing, though, I believe that Oracle will insist that you must
license the additional machine. If you don't plan that the machine would
actually be for fail-over, though, I suppose that the additional license for
a manual solution could be for quite a modest machine and a small number of
users. I'm not sure whether the latest specification for the DataGuard
license requires licensing for the same level as the primary machine (albeit
with discounts), but a small machine manual standby certainly opens the
question of possible major savings. Some folks over the years have
negotiated things such as loading an alternate system for verification of
the integrity and recoverability of backups, but I think Oracle tends to put
a "certain number of times per year" limit in new licenses covering that
issue.
Regards,
mwf
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx]On Behalf Of Rachel Carmichael
Sent: Monday, September 27, 2004 5:43 AM
To: niall.litchfield@xxxxxxxxx; identd@xxxxxxxxx
Cc: oracle-l@xxxxxxxxxxxxx
Subject: Re: options for read only mirror with 10g SE or SE One
major deletions to not fail the 80% rule..
Manual standby was unsupported in 7.3.4 but was possible as part of
"recovery". I learned this by playing when I was testing my recovery
scripts.... I was able to just keep handing the recovery process
archived logs that were past the date of the crash and Oracle merrily
kept up.
I *think* this was documented in a white paper by Lawrence To at that
time .
> I'm afraid I don't understand this. You are asking for a read-only
> copy of a database and don't require automated failover. Manual
> standby gives you this and has done since at least version 8 (I
> *believe* since 7.3.4) . It isn't DataGuard but it doesn't sound like
> it needs to be for you (or the cost of DataGuard is unattractive for
> you - which I understand).
>
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