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[oracle-l] Re: Double-Take for Oracle?

From: Carel-Jan Engel <>
Date: Fri, 23 Jan 2004 21:19:31 +0000
Message-Id: <>

Hi Paul,
Is the connection between your sites pushed to the limits? You can use ssh, with compression and port forwarding, to get the redo info compressed. It's described in (note 225633.1). Depends on the DG-method used. SSH/port forwarding won't bring you much improvement using LGWR SYNC, but can do so significantly in ARCH ASYNC mode.

I'm sorry , I don't know the Double-Take stuff you described. What I would take into consideration is how to verify and monitor that the standby system actually gets synchronised, and what time instatiation takes. Is switchover possible? Otherwise a failover for switchover puposes might take a lot of time for re-instantiation, resulting in longer vulnerable periods with only one database available.

Regards, Carel-Jan

At 05:22 PM 1/23/2004, you wrote:
>We're setting up a Data Guard physical standby here at our office; the
>primary database is at a colocation facility about 100 miles away, with
>a T1 currently providing networking between the two sites. The T1 is
>inadequate to keep up with the rate of redo generation during batch
>operations (like imports) on the primary.
>Our IT suggested that I look at NSI's Double-Take, which claims to
>replicate only byte-by-byte changes, and to support Oracle. I have two
>questions for anyone who's used or considered using this product:
>1. Does Double-Take appreciably reduce network traffic compared to
>Data Guard physical standby?
>2. Does Double-Take work reliably with Oracle? Does Oracle support a
>database that is replicated using this product?
>Paul Baumgartel
>Transcentive, Inc.
>Do you Yahoo!?
>Yahoo! SiteBuilder - Free web site building tool. Try it!

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e-mail Received on Fri Jan 23 2004 - 15:19:31 CST

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