Xref: alice comp.databases.oracle.server:35790 Path: alice!news-feed.fnsi.net!news.maxwell.syr.edu!news-peer1.sprintlink.net!news-in-east1.sprintlink.net!news.sprintlink.net!nntp1.wolfe.net!news.wolfe.net!gonzo.wolfenet.com!jeremiah From: Jeremiah Wilton Newsgroups: comp.databases.oracle.server Subject: Re: Backup/Recovery of RBS datafiles Date: Fri, 11 Dec 1998 22:23:44 -0800 Organization: Wolfe Internet Access, L.L.C Lines: 31 Message-ID: References: <367168c1.20068785@news1.axs2000.net> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII To: Chuck Hamilton In-Reply-To: <367168c1.20068785@news1.axs2000.net> On Fri, 11 Dec 1998, Chuck Hamilton wrote: > > Is it really necessary to include rollback segment datafiles in every > backup? We'd save about 8g on our backups if we didn't. Is there any > easy way to rebuild them if we needed to? If you take a backup without the rollback segment datafiles, and you then use that backup to do any kind of recovery other than a complete recovery up to the point of a clean shutdown (normal or immediate), there will be open transactions that will have to roll back in order for the database to function properly. Without a copy of the rollback segments, you won't have the data to roll those transactions back. So under most recovery scenarios, rebuilding the rollback segments after the fact is probably not a possibility. > One thought I had was to keep one copy of the RBS datafiles and if we > ever had to recover, we could just restore it from that backup and do > a recovery on it. You might as well just make one copy of the whole database, because you will have to apply just as much redo in order to perform a recovery. Although it is faster to apply redo to just one tablespace than it is to apply redo to the whole database, you would still have to find all the right redologs to apply. I think the best strategy is a nightly full hot backup. If that is too large for your media, then half one day and half the next might be all right, depending on your mean time to recovery requirements. -- Jeremiah Wilton http://www.wolfenet.com/~jeremiah