Re: Re[2]: 2 Node RAC Standby -- A mix of Managed Recovery and Read only?

  • From: Carel-Jan Engel <cjpengel.dbalert@xxxxxxxxx>
  • To: spatenau@xxxxxxxxx
  • Date: Thu, 06 Jan 2005 20:20:40 +0100

A read-only standby can continue receiving redo. So, the only risk is
extra downtime, because there is more redo to apply when the primary
fails whilst the standby is in R/O mode. Your description is a perfect
way of eating the cake and have it: run reports on the standby during
office hours, of course with data actualized up till the morning, and
let the standby apply the receive logs during the night. There is always
a standby, the recovery time of it may vary.
I didn't know of the 'mixed standby setup' you mentioned. Thank you for
bringing this up. Another challenge on my todo list for future tests.

Best regards,

Carel-Jan Engel

If you think education is expensive, try ignorance. (Derek Bok)

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On Thu, 2005-01-06 at 18:46, Steven Patenaude wrote:

> On Thu, 06 Jan 2005 20:02:17 +0800, Kamus <kamusis@xxxxxxxxx> wrote:
> > Sorry, I don't think so.
> > First, the storage is cheaper and cheaper this days, buy onemore cheap
> > dell-emc Storage System maybe enough.
> > Second, by setting up 2 independent standby databases we could get a
> > much more flexible anti-disaster environment. such as 1 be a physical
> > and the other be a logical, or 1 be a instant apply and the other be a
> > delayed apply, etc...
> While _we_ know the one true way, management often doesn't agree that
> disk hardware, maintenance costs, datacenter floor space, etc. is
> cheap (or cheap enough).
> I don't remember (and need to get on with my day job), does a standby
> database continue to catch the redo stream (but not apply it) while it
> is in readonly mode?  If so, you could alternate the standby between
> readonly and "catch up" modes as needed.
> > Though oracle said standby database support RAC, at least so far I won't
> > use this function.
> Obviously the standby can be configured for RAC but I agree about only
> having one instance up.  The documentation says you can have one
> instance catch the redo stream and another apply it.  Has anyone tried
> this?  It seems to me this would be added complexity (and chances for
> problems) with very minimal performance gains.
> Steven
> --
> //


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