Backup Isn't Enough

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Backup Isn't Enough

Steve Jones - SSC Editor

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July 17, 2010 at 11:48 am

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Comments posted to this topic are about the item Backup Isn't Enough

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george sibbald SSC Guru Points: 104210 More actions · Answer 1

good point.

Garbage in, garbage out OR garbage backed up garbage recovered

also the ability to build a delay into log shipping is an oft forgotten advantage of this old workhorse HA method over the fancier and therefore presumed better in all aspects mirroring and clustering

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Cyclone Mr or Mrs. 500 Points: 560 More actions · Answer 2

Hi ....

In our datawarehouse environment we have added the fields ExtractDate, LatestEntryIndicator, EntryStartDate, and EntryEndDate to all dimension and fact tables. Using these fields we are able to rollback the data to a specific point in time, removing any suspect data that may have been loaded into the warehouse. We carry out daily differential and monthly full backups of the datawarehouse databases.

The backups are essentially to cater for a server related failure whereas the rollback process is in order to cater for a recovery from suspect data.

This strategy seems like it would be able to recover the database to a reliable state in the event of either type of "catastrophe".

Cheers.

jay-h SSCoach Points: 18816 More actions · Answer 3

The ability to selectively recover from bad data input should really be part of the initial database design. It's not enough to have 'point in time" because substantial transactions may have occurred in the interim before discovery. You really can't afford to manually review multiple thousands of entries. Transactions need to be fully indentified and preserved (in an append only table, for example). This involves careful planning with the business rules.

It's expensive in development time, but if there is a potential need it is worth it.

...

-- FORTRAN manual for Xerox Computers --

SQLRNNR SSC Guru Points: 281334 More actions · Answer 4

I hate those "garbage" sources. It is quite difficult to trust any data in the database when the source of the data is known to be suspect.

Jason...AKA CirqueDeSQLeil
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I have given a name to my pain...MCM SQL Server, MVP
SQL RNNR
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