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

From: Carel-Jan Engel <cjpengel.dbalert_at_xs4all.nl>
Date: Fri, 23 Jan 2004 21:19:31 +0000
Message-Id: <6.0.1.1.0.20040123210853.447dc110@pop.xs4all.nl>

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
http://metalink.oracle.com/metalink/plsql/showdoc?db=NOT&id=225633.1&blackframe=0 (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?
>
>TIA
>
>
>
>=====
>Paul Baumgartel
>Transcentive, Inc.
>www.transcentive.com
>
>__________________________________
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e-mail info.dbalert_at_xs4all.nl Received on Fri Jan 23 2004 - 15:19:31 CST