Re: 2nd Archive Destination Question

"Paul Drake" <drak0nian_at_yahoo.com> wrote in message news:1ac7c7b3.0211161253.5408dce4_at_posting.google.com...
> Chuckster <chuckycarson_at_networkcloud.com> wrote in message
news:<3DD2F268.1040107_at_networkcloud.com>...
> > Under Oracle 8.1.7, if you specify two archive destinations, will the
> > database hang if one of the destinations run out of space? (ie: It can
> > still right to the other destination)
> >
>
> Chuckster,
>
> not related to a standby is
>
> duplexing the archived redo logs - locally.
>
> if you specified a parameter/value in the init.ora for
>
> log_archive_duplex_dest
>
> then both destinations are statically mandatory.
>
> Paul

That's not actually true, Paul. First of all, let's distinguish between LOG_ARCHIVE_DEST/LOG_ARCHIVE_DUPLEX_DEST (which are your only options in the Standard Edition, and anything prior to 8i) and LOG_ARCHIVE_DEST_n, where "n" can be anything from 1 to 5 (in 8i Enterprise Edition) or 1 to 10 (in 9i Enterprise Edition).

If you use the _ARCHIVE_DEST/_DUPLEX_DEST combination, then you have also to be aware of the LOG_ARCHIVE_MIN_SUCCEED_DEST parameter. That can be set to either 1 or 2. It defaults to 1. Meaning that, by default, only one of the archiving destinations is considered mandatory, and the one that is assumed to be mandatory is the LOG_ARCHIVE_DEST one. If you set it explicitly to 2, then both are considered mandatory.

Point being, merely setting the DUPLEX_DEST does *not* make both destinations "statically mandatory", but would only imply the _DEST destination was.

If you are using the newer _DEST_n parameters, then by default all of them are considered to be OPTIONAL. Except that MIN_SUCCEED_DEST can be still be used with the newer parameters, and it still defaults to 1, so that the LOG_ARCHIVE_DEST_1 is assumed to be mandatory. All others would, however, be OPTIONAL. If you explicitly set MIN_SUCCEED_DEST to 2, it's maximum setting, whilst using the newer parameters, then *one* of the other destinations is silently changed from its default OPTIONAL to an implicit MANDATORY. However, you've no control over which of the other destinations is so altered, and it can change: so if you've set 5 archiving destinations, and MIN_SUCCEED_DEST to 2, then the first is mandatory, and any of the other 4 will be considered mandatory for a particular archiving operation... but each of the other 4 can be regarded as 'mandatory' at different times as new archives are processed. Combine all 4 destinations together, in other words, and you'd be guaranteed a complete archive sequence.

Personally, I think that is such a palaver that I recommend NOT setting MIN_SUCCEED_DEST with the newer parameters, and instead explicitly set OPTIONAL and MANDATORY switches for the listed DEST_n destinations.

Regards
HJR Received on Sat Nov 16 2002 - 15:56:25 CST