Re: how hot is a hot backup?
Date: 1996/02/25
Message-ID: <4gq6id$nee_at_news.acns.nwu.edu>#1/1
In article <312f60c1.186608437_at_news.brookings.net>,
kasten_at_brookings.net (Chris Kasten) wrote:
>Concerning Replication and Hot Backups.
>
>We'll be doing replication with one of the goals
>being hot backups (ie: redundancy).
in oracle language, hot backup merely means that you are backing up while the database is open. by contrast cold backup means the database is closed. replication isn't really a backup of a database strictly speaking because the replication could be interrupted; hence the replicated db is different from the down db. that's not a backup!
> When one
>machine falls apart, what exactly is necessary to
>switch the world to the other one? Can this be
>done transparently? Better yet - are there some
>white papers floating around?
a solution is to have completely separate machines with disk and user input mirrors -- no contact between machines -- and a switch someone can throw to toggle the alternate iron. detecting the failure of one machine is an interesting problem since some fail modes just leave you hanging and are indistinguishable from "busy" conditions.
-- Dave Mausner, Consulting Manager, Braun Technology Group, Chicago.Received on Sun Feb 25 1996 - 00:00:00 CET