Re: Rman issue

Arun,

Let me see if I understand your problem. You feel RMAN is using too much I/O, and you want to reduce that? I'm assuming that RMAN is not leaving enough I/O for other processes that are running at the same time? You tried reducing the channels to 4 since you have 4 controllers?

    What are you writing the RMAN backups to -- disk or tape? Usually the target system is what limits the I/O, and usually that limitation is a problem, not the source disk system.

    If RMAN uses less I/O, it will take longer to complete, which will extend the contention with other processes. Perhaps you can rearrange the competing processes in terms of time to experience less contention.

    My guess is that you should try fewer channels than controllers in order to reduce RMAN's I/O rate. You probably need to reduce the number of channels below 4, to 3 or 2.

     I have not used the diskratio parameter, perhaps someone else on the list has.

Dennis Williams

On 7/11/05, arun chakrapani rao <arunrao_oradba_at_yahoo.co.in> wrote:
> Hi gurus,
> Has anybody used diskratio parameter in rman, if so
> have u seen any benefits using that
> I am seeing a very high io used by rman here on a prod
> box which is running on hp itanium.

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