Re: L:ist - Can do/do better in MS SQL than Oracle

Niall Litchfield wrote:
>
> Oracle ships out of the box with a product that allows you to backup only
> changed blocks from datafiles (RMAN). As far as I know MS doesn't provide
> this level of functionality which will help massively on very large
> databases.

I'd like to hear from shops using RMAN to backup very large databases. I have admittedly little RMAN experience - literally only what I've read. But I haven't read anything about it that would convince me to use it for very large (say, 500 gig and up) databases. Incrementals are certainly a nice feature, but most shops will still usually want to do full backups on a regular (typically weekly) basis with daily incrmentals. For that size db, you almost have to use a modern split-mirroring technology and good old-fashioned hotbackups to take a full backup in any sort of reasonable timeframe without impacting performance on the database for an extended period. In other words, how long will it take RMAN to do a full backup of a 2 terabyte database? I'm guessing quite a while. And during that while, won't the performance of the database be impacted?

With regular hotbackups and a split-mirror or snapshot technology (EMC, NetApp, what have you), the database is only affected for the time it's in hotbackup mode - a few minutes tops. After the mirror is split off or the snapshot taken, we have all the time in the world to take it to tape or do whatever else (clone it, etc.).

So... any shops out there actually using RMAN for the big stuff? How do you like it?

Thanks,
Sean Received on Thu Mar 28 2002 - 10:20:10 CST