From: "Howard J. Rogers" Newsgroups: comp.databases.oracle.server References: <95el51$3k7$1@nnrp1.deja.com> Subject: Re: Hot Backup Lines: 45 X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 5.50.4133.2400 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4133.2400 X-Original-NNTP-Posting-Host: 203.134.154.74 Message-ID: <3a7b427a$1@news.iprimus.com.au> X-Original-Trace: 3 Feb 2001 10:27:54 +1100, 203.134.154.74 Date: Sat, 3 Feb 2001 10:28:01 +1100 NNTP-Posting-Host: 203.134.64.67 X-Trace: news0.optus.net.au 981156477 203.134.64.67 (Sat, 03 Feb 2001 10:27:57 EST) NNTP-Posting-Date: Sat, 03 Feb 2001 10:27:57 EST Organization: CWO Customer - reports relating to abuse should be sent to abuse@cwo.net.au What's redo for? To apply to inconsistent copies of datafiles, so that they can be made consistent, and thus continue to be used after recovery. If you do a hot copy of your redo logs, they will be inconsistent, too. What do you propose to apply to redo logs to make them consistent? (Hint: you can't apply redo to redo logs). In short, the answer is that you do NOT copy redo logs when a database is backed up hot (theoretically, you don't need to do so when it's backed up cold, either -but most people do, and it makes things much easier at recovery time -but that's only for COLD backups, because we can thereby guarantee that the logs are internally consistent). If you DO copy them, they will be unuseable. What's worse, you may be tempted when disaster strikes to restore them on top of perfecly good redo logs -bye-bye data. If the current redo log ever gets corrupted (and mirroring redo internally with Oracle's own mechanisms is designed, in part, to make that highly unlikely), then you are looking at performing an incomplete recovery -a recover database until cancel, and kiss goodbye to all transactions that were sitting in that last log. Regards HJR wrote in message news:95el51$3k7$1@nnrp1.deja.com... > Hi, > I take a hotbackup daily and make a backup of the controlfile after > doing alter system switch logfile; > My question is I don't take a backup of redo logs.I have them > mirrored and everything.Should I take a backup of redo logs also. > If the current member of redo logs get corrupted how is the > recovery done. > Regards, > Ashish > > > Sent via Deja.com > http://www.deja.com/