Re: Ocopy and Archived Logs
Date: Tue, 8 Dec 2009 15:19:55 -0800 (PST)
On Dec 8, 2:38 pm, Gary <gjwater..._at_gmail.com> wrote:
> ddf wrote:
> > There is no such command; ocopy is merely the standard copy command
> > 'gussied up' to allow it to copy files currently in use. It is not a
> > fully featured backup utility; for that you use RMAN.
> > David Fitzjarrell
> I figured as much. Thanks for the response.
> The trouble I'm having is knowing when to remove unneeded archive logs.
> Currently, I remove older logs based on the file creation date. I figure
> that retaining logs created at least a day before the most recent
> successful backup should guarantee that the first archive log in the
> restore sequence will be present. This is error prone, I know. I was
> hoping the DB would keep track of the name of the first archive log
> after the ocopy was started, but seeing as ocopy just concurrently
> copies the datafiles, it makes sense that it doesn't.
> Regarding RMAN vs ocopy, I inherited this setup and plan to change it in
> the future. To what, I'm not sure. I've heard RMAN is complicated (never
> used it). I'm after something simple like exp, but faster.
RMAN could be complicated, but for simple use, it is simple. What version are you on? For any recent version, it is simpler than any other way. It also has commands so you can have it figure out if what it needs is around, or what it would need if it isn't. There are situations where you need something older than the first archive log after the copy was started. Don't forget, there are things going on in the background, too.
RMAN stands for Recovery Manager, which is a lot more important than backups, right? See the backup manuals for examples.
If you are on fully patched 10gR2 or above and have dbcontrol, default backup is almost good enough (though I'd recommend copying the backup command it makes elsewhere for when it screws up). Just a few configuration changes are necessary, site dependent - you can tell it things like retention policies. The compressed backups work good, and wind up being quicker than any other backup method plus compression. Also, RMAN is smarter than user managed backups as far as fractured blocks (look it up), it doesn't have to generate excess redo because of placing files in backup mode.
All the other stuff it does is icing. Really good icing if your management decides it is needed.
-- _at_home.com is bogus. http://www.signonsandiego.com/news/2009/dec/05/sec-slaps-nova-gen-charges/Received on Tue Dec 08 2009 - 17:19:55 CST