MaxCorrupt

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08-05-2002, 02:57 AM
hany

hi guys,
i'm currently doing the backup scripts for my production database, and i need to know if it's a good idea to always use the 'Set MaxCorrupt for datafile n to 0'.

i find it very useful that i will always have a usable, and reliable backup, but i also need to know from you guys if there is any disadvantage in using this parameter in such a way.

Regards.
08-06-2002, 02:13 AM
hany

anyone has an answer?

Regards.
08-06-2002, 03:03 AM
julian

I think that the default for MAXCORRUPT is 0. So you do not have to set it explicitely in the script.
08-06-2002, 03:20 AM
hany

Quote:

Originally posted by julian
I think that the default for MAXCORRUPT is 0. So you do not have to set it explicitely in the script.

Then i guess it means that i will always have a corruption free backups (copies) if i leave the default value as it is, right?.

Does that mean that i will query v$backup_corruption, and v$copy_corruption only if i set maxcorrupt to a number > 0?

One more thing i need to clarify please, why would anyone set the maxcorrupt to a number > 0?

the block media recovery (BMR) feature in 9i is meaningless unless i set the value of maxcorrupt to a number > 0 (which i don't know why would anyone want to do), right?

Thanks Julian.
08-06-2002, 03:40 AM
julian

Quote:

Originally posted by hany

Quote:

Originally posted by julian
I think that the default for MAXCORRUPT is 0. So you do not have to set it explicitely in the script.

Then i guess it means that i will always have a corruption free backups (copies) if i leave the default value as it is, right?.

Yes. This is from the Oracle documentation:

"MAXCORRUPT sets a limit on the number of previously undetected physical block corruptions that Oracle will allow in a specified datafile or list of datafiles. If a BACKUP or COPY command detects more than the specified number of corruptions, the command aborts. The default limit is zero, meaning that RMAN tolerates no corrupt blocks."

Quote:

Does that mean that i will query v$backup_corruption, and v$copy_corruption only if i set maxcorrupt to a number > 0?

Yes.

Quote:

One more thing i need to clarify please, why would anyone set the maxcorrupt to a number > 0?

Thanks Julian.

Good question! Probably if you really need the backup and don't care about some corrupted blocks hoping possibly they they are index blocks. So that you can then drop and recreate the indexes. I really don't know :-)
08-06-2002, 03:48 AM
hany

Thank you Julian, i really appreciate your help.

Cheers.