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

Were you to stick around for another couple of versions, it wouldn't surprise me in the least if you were to hear an announcement that RMAN is to be the only supported method of taking backups.

The push is on (as of 9i) to get people to use it; they've invested heavily in simplifying the syntax and making it useable; it's a tool they know from the inside, so they know what it is doing. O/S backups, by contrast, are in the lap of the gods (well, the mindset of the users, anyway).

I know one 3Tb site using perfectly happily. The performance impact is negligible (largely because they limit the I/O rate on the channels doing the backup so no-one notices it), and it chugs on in the background for most of the day.

HJR

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"Sean M" <smckeownNO_at_BACKSIESearthlink.net> wrote in message
news:3CA342CD.5D1DA6AF_at_BACKSIESearthlink.net...


> 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