Re: RMAN Archivelog question

On Tue, 9 Sep 2008 06:50:09 -0700 (PDT), artmerar_at_yahoo.com wrote:

>On Sep 8, 4:47 pm, sybra..._at_hccnet.nl wrote:
>> On Mon, 8 Sep 2008 11:01:47 -0700 (PDT), artme..._at_yahoo.com wrote:
>> >If you use the DELETE INPUT in your backup command (PLUS ARCHIVELOG),
>> >would you even need to do a crosscheck?
>>
>> A crosscheck is necessary when someone decides to delete backups or
>> archivelogs without using RMAN, ie directly from the OS.
>>
>> It is appreciated
>> a) you answer doc questions yourself by reading the docs
>> b) don't ask questions two times within a few minutes.
>>
>> --
>> Sybrand Bakker
>> Senior Oracle DBA
>
>Sybrand,
>
>Sometimes the documentation is not really clear. For example, if I
>use a recovery window, say 2 weeks, and my archive logs are included
>in my level 0 backup and I use a DELETE INPUT to remove the archive
>logs. Why would I need a crosscheck for archive logs? They are
>included in the backup, and they have been removed once backed up.
>Additionally, I'm assuming that I would not need a 'DELETE ARCHIVELOG'
>statement either.
>
>The docs are not very clear on this........
>
>Regards.

The very purpose of crosscheck is to repair inconsistencies between disk (or tape library) and catalog (whether in a controlfile or in a separate catalog database). Crosscheck marks entries in the catalog which no longer exist on disk or in the tape library as deleted. Inconsistencies mainly arise from administrators not using RMAN to maintain their backups.
If you solely use RMAN to maintain backups and archivelogs, you shouldn't need to run crosschecks.
Apart from that running crosscheck prior to a backup implicitly only checks the consistency of prior backups. Which is why it is redundant.

-- 
Sybrand Bakker
Senior Oracle DBA