Re: Oracle archive mode and hot backups
From: ddf <oratune_at_msn.com>
Date: Fri, 7 Aug 2009 06:20:18 -0700 (PDT)
Message-ID: <772770bf-1348-411c-b125-bc72e29af9b8_at_r27g2000vbn.googlegroups.com>
On Aug 7, 8:11 am, "Preston" <dontwant..._at_nowhere.invalid> wrote:
> ddf wrote:
> > On Aug 7, 6:13 am, "Preston" <dontwant..._at_nowhere.invalid> wrote:
> > > John Hurley wrote:
> > > > On Aug 6, 8:05 pm, Palooka <nob..._at_nowhere.com> wrote:
>
> > > > snip
>
> > > > > > If you are not really in production on this system ...
> > > > > > ditching the archive logs can be done as needed probably.
>
> > > > > > Maybe the archive log files are being put into different
> > > > > > locations simultaneously ( multiple copies ) so that copy
> > > > > > that was getting ditched really is un-necessary.
>
> > > > > > Best advice is to ask the relevant DBA a couple more questions
> > > > > > and get them to explain exactly what is going on.
>
> > > > > What a load of bollocks. Sybrand is entirely right. What on
> > > > > earth is the
>
> > > > Best advice is to ask the relevant DBA a couple more questions
> > > > and get them to explain exactly what is going on.
>
> > > Exactly that. Jeff didn't say this script would delete all the
> > > archive logs (it might leave whatever's necessary to recover between
> > > backups), nor if these are the only copies, not if it's a full
> > > backup every night etc etc. Nobody has enough information to say
> > > whether this is bad or not, but of course that won't stop the usual
> > > suspects shouting 'hang him!'.
>
> > Let's look at what has been reported thus far:
>
> > "The DBA state that the standard
> > is to have the database in archive mode to allow for hot backups. "
>
> > Again, it's not a 'standard', it's an available option.
>
> It may be that company's standard.
>
> > And, yes,
> > archivelog mode is required to allow for a hot (online) backup
> > strategy, priimarily because these logs are NECESSARY for recovery, a
> > concept apparently lost on this 'DBA' as evidenced by this next quote:
>
> They are necessary for recovery up to the point where they're no longer
> necessary.
>
>
>
>
>
>
>
> > "We ran into an issue when the 17 gigs of space in the archive folder
> > was full. The DBA's solution was to write a script to automatically
> > delete archive files when the folder reaches 10 gigs. I questioned
> > the need to create archive files if they are ultimately deleted.
> > **** The DBA stated that the actual archive files are not used and
> > can be
> > deleted. The archive mode is only used for hot backups. ****"
>
> > Given that level of 'knowledge' one expects these archivelogs are
>
> > -- considered irrelevant to the recovery process by the 'DBA'
> > -- are NOT treated to a proper backup prior to deletion
>
> > From that we can deduce:
>
> > -- this 'DBA' has no concept of recovery from a hot (online) backup
> > and feels that simply the backup itself is sufficient
> > -- this 'DBA' has yet to attempt a recovery from one of his hot
> > backups
>
> > I'm interested in how you arrived at your apparently erroneous
> > conclusions given the information posted above.
>
> You're just making wild assumptions, based on very limited information
> given by a 3rd party when summing up what someone else has said. You
> don't know if he's planning to delete *all* archive logs. You don't
> know if those logs are backed up elsewhere. You don't know if those
> logs are applied to cumulative nightly backups.
>
> Yes, it may be the DBA's clueless. Or it may be he's superb, & didn't
> want to go into all the details of explaining RMAN to a layman. The
> only way for the OP to find out is to ask more questions, based on the
> information he gets from places like cdos.
>
> --
> Preston- Hide quoted text -
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -
Date: Fri, 7 Aug 2009 06:20:18 -0700 (PDT)
Message-ID: <772770bf-1348-411c-b125-bc72e29af9b8_at_r27g2000vbn.googlegroups.com>
On Aug 7, 8:11 am, "Preston" <dontwant..._at_nowhere.invalid> wrote:
> ddf wrote:
> > On Aug 7, 6:13 am, "Preston" <dontwant..._at_nowhere.invalid> wrote:
> > > John Hurley wrote:
> > > > On Aug 6, 8:05 pm, Palooka <nob..._at_nowhere.com> wrote:
>
> > > > snip
>
> > > > > > If you are not really in production on this system ...
> > > > > > ditching the archive logs can be done as needed probably.
>
> > > > > > Maybe the archive log files are being put into different
> > > > > > locations simultaneously ( multiple copies ) so that copy
> > > > > > that was getting ditched really is un-necessary.
>
> > > > > > Best advice is to ask the relevant DBA a couple more questions
> > > > > > and get them to explain exactly what is going on.
>
> > > > > What a load of bollocks. Sybrand is entirely right. What on
> > > > > earth is the
>
> > > > Best advice is to ask the relevant DBA a couple more questions
> > > > and get them to explain exactly what is going on.
>
> > > Exactly that. Jeff didn't say this script would delete all the
> > > archive logs (it might leave whatever's necessary to recover between
> > > backups), nor if these are the only copies, not if it's a full
> > > backup every night etc etc. Nobody has enough information to say
> > > whether this is bad or not, but of course that won't stop the usual
> > > suspects shouting 'hang him!'.
>
> > Let's look at what has been reported thus far:
>
> > "The DBA state that the standard
> > is to have the database in archive mode to allow for hot backups. "
>
> > Again, it's not a 'standard', it's an available option.
>
> It may be that company's standard.
>
> > And, yes,
> > archivelog mode is required to allow for a hot (online) backup
> > strategy, priimarily because these logs are NECESSARY for recovery, a
> > concept apparently lost on this 'DBA' as evidenced by this next quote:
>
> They are necessary for recovery up to the point where they're no longer
> necessary.
>
>
>
>
>
>
>
> > "We ran into an issue when the 17 gigs of space in the archive folder
> > was full. The DBA's solution was to write a script to automatically
> > delete archive files when the folder reaches 10 gigs. I questioned
> > the need to create archive files if they are ultimately deleted.
> > **** The DBA stated that the actual archive files are not used and
> > can be
> > deleted. The archive mode is only used for hot backups. ****"
>
> > Given that level of 'knowledge' one expects these archivelogs are
>
> > -- considered irrelevant to the recovery process by the 'DBA'
> > -- are NOT treated to a proper backup prior to deletion
>
> > From that we can deduce:
>
> > -- this 'DBA' has no concept of recovery from a hot (online) backup
> > and feels that simply the backup itself is sufficient
> > -- this 'DBA' has yet to attempt a recovery from one of his hot
> > backups
>
> > I'm interested in how you arrived at your apparently erroneous
> > conclusions given the information posted above.
>
> You're just making wild assumptions, based on very limited information
> given by a 3rd party when summing up what someone else has said. You
> don't know if he's planning to delete *all* archive logs. You don't
> know if those logs are backed up elsewhere. You don't know if those
> logs are applied to cumulative nightly backups.
>
> Yes, it may be the DBA's clueless. Or it may be he's superb, & didn't
> want to go into all the details of explaining RMAN to a layman. The
> only way for the OP to find out is to ask more questions, based on the
> information he gets from places like cdos.
>
> --
> Preston- Hide quoted text -
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -
And I hope, for their peace of mind, you're correct regarding this DBA's credentials and knowledge. Given what's been posted thus far I cannot foresee that you have performed an accurate assessment given this 'nugget of wistom':
"The DBA stated that the actual archive files are not used and can be deleted. The archive mode is only used for hot backups."
"No longer needed" is a MUCH different concept than "not used". And I have seen no mention of RMAN usage in the original post, plus the tone of concern from the OP given that his research resulted in a much different assessment than that which was provided him by this 'DBA'.
David Fitzjarrell Received on Fri Aug 07 2009 - 08:20:18 CDT