Re: VM vs Data Guard for DB redundancy

Sorry. I was referring to the idea of having multiple standby dbs with different latencies.

--
Fernando.

To educate a man in mind and not in morals is to educate a menace to
society.
Theodore Roosevelt


On Tue, Jul 19, 2016 at 1:05 PM, Seth Miller <sethmiller.sm_at_gmail.com>
wrote:



> Fernando,


>

> Can you provide some context for this?

>

> What comment from which individual are you responding to?

>

>

>

>

> On Tue, Jul 19, 2016 at 11:12 AM, Fernando N. de Souza <fnantes_at_gmail.com>

> wrote:

>

>> Or you could have only one standby db in flashback mode.

>>

>> On Jul 17, 2016 10:37 PM, "Connor McDonald" <mcdonald.connor_at_gmail.com>

>> wrote:

>>

>>> For me ... the nice thing with DataGuard is customisable latency.

>>>

>>> Because its rarely hardware etc nowadays that causes a "disaster"....its

>>> that errant installation script that did

>>>

>>> drop table THE_MOST_IMPORTANT_TABLE_IN_MY_COMPANY;

>>>

>>> and it doesn't matter how many VM's you have floating around if you only

>>> have 1 database :-)

>>>

>>> So I can have 1 DG with 'zero' latency, 1 DG with 2hours latency, 1 with

>>> a day etc etc etc...

>>>

>>>

>>>

>>>

>>>

>>>

>>> On Wed, Jun 29, 2016 at 6:23 AM, Mark W. Farnham <mwf_at_rsiz.com> wrote:

>>>

>>>> 365.25 * .01 = 3.6525 days. I think you're quoting for a few more 9's.

>>>>

>>>>

>>>> -----Original Message-----

>>>> From: oracle-l-bounce_at_freelists.org [mailto:

>>>> oracle-l-bounce_at_freelists.org] On Behalf Of Stefan Koehler

>>>> Sent: Tuesday, June 28, 2016 4:11 PM

>>>> To: woody.mckay_at_gmail.com; ORACLE-L

>>>> Subject: Re: VM vs Data Guard for DB redundancy

>>>>

>>>> Hey Woody,

>>>> well before going into any technical details, you need to define

>>>> clearly what your RPO and RTO is about. I mean you already mentioned an

>>>> uptime of 99% and max downtime of 45 minutes, but in what scale? Per month?

>>>> Per year? Per week? Per day? With system maintenance  windows or not? For

>>>> example a downtime of 99% per year is 5.256 minutes which does not really

>>>> fit to your 45 minutes, but a downtime of 99% per day is 14,4 minutes which

>>>> does not really fit to your 45 minutes as well.

>>>>

>>>> After you got these detailed requirements from the business owner, you

>>>> need to clarify RPO in detail ("You would lose in-flight, but that appears

>>>> to be acceptable" is not enough definition at all).

>>>>

>>>> There may be also legal statements (e.g. like from BSI in Germany -

>>>> https://www.bsi.bund.de/SharedDocs/Downloads/DE/BSI/Hochverfuegbarkeit/BandB/B8_Datenbanken.pdf),

>>>> which clearly state that only a virtualization solution is not sufficient

>>>> for RDBMS HA, but this is country/environment dependent of course. You

>>>> should check this with your state and planned systems.

>>>>

>>>> Be also aware that virtualization only catch host failures. You still

>>>> have to deal with logical and physical corruption (and detection) on RDBMS

>>>> level, which has to be set in relation to your defined RPO / RTO and

>>>> database size, etc..

>>>>

>>>> Best Regards

>>>> Stefan Koehler

>>>>

>>>> Freelance Oracle performance consultant and researcher

>>>> Homepage: http://www.soocs.de

>>>> Twitter: _at_OracleSK

>>>>

>>>> > Woody McKay <woody.mckay_at_gmail.com> hat am 28. Juni 2016 um 17:47

>>>> geschrieben:

>>>> >

>>>> >  Hi,

>>>> >

>>>> >  In a few days, I need to start investigating maintenance and

>>>> viability for a DB redundancy solution for 2,700 Oracle 12.1.0.2 databases

>>>> on Linux.

>>>> >  Currently, the 2,700 customers are in individual instances, but will

>>>> be looking to put them into PDB's later this year.

>>>> >

>>>> >  Leadership has told me that RAC is not an option to be considered.

>>>> > Only Data Guard and VM with external storage.  If the VM goes down,

>>>> the thought is to bring up another VM and mount the original storage

>>>> (san).  It's obvious what to do with Data Guard.

>>>> >

>>>> >  I thought I'd check with the pros here to see what the rest of the

>>>> best are doing.

>>>> >

>>>> >  What are the best options for DB redundancy?  Considering

>>>> > maintenance, cost and overall viability.  Want to be up 99% and

>>>> downtime is limited to 45 minutes or less.

>>>> >

>>>> >  The VM option sounds interesting. Just bring up a new VM on the same

>>>> IP and mount the same storage - viola. No app fail-over or DNS change, etc.

>>>> >  Got just one DB cost.  You would lose in-flight, but that appears to

>>>> be acceptable.

>>>> >

>>>> >  Thoughts, pros/cons ?  Other better solutions?

>>>> >

>>>> >  --

>>>> >  Sincerely,

>>>> >

>>>> >  WoodyMcKay

>>>> --

>>>> http://www.freelists.org/webpage/oracle-l

>>>>

>>>>

>>>> --

>>>> http://www.freelists.org/webpage/oracle-l

>>>>

>>>>

>>>>

>>>

>>>

>>> --

>>> Connor McDonald

>>> ===========================

>>> blog:   connormcdonald.wordpress.com

>>> twitter: _at_connor_mc_d

>>>

>>> "If you are not living on the edge, you are taking up too much room."

>>> - Jayne Howard

>>>

>>> *Fine print: Views expressed here are my own and not necessarily that of

>>> my employer*

>>>

>>

>


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