Re: Curiosity question - Bandwidth using RMAN duplicate from Serivce

On 2/28/19 10:54 PM, Tiwari, Yogesh wrote:
>
> Mladen,
>
> " One channel on a physical Linux box  typically does around 350 GB/hr
> when compression is used. It's around 7.5 MB/sec. "
>
> Mate, do you mean a single channel is throttled within Oracle itself?
> Why do we need 10 channels on a 10G net to get 3.5T/hr? Is it documented ?
>
I am not sure why the numbers are what they are, and I have the same experience with NetBackup, which I used to use before going to work for Commvault. I don't think it's documented. Throttling from within Oracle may be a reason. Namely, RMAN has to briefly lock blocks before writing them to the output channel, to prevent inconsistencies. However, the detailed mechanism is proprietary and, as such, unlikely to be documented. After all, that is the reason for having multiple channels. If a single channel was able to consume the entire available network bandwidth, why would you need more than one channel in the first place? This is simply my experience. I'd very much like to hear if you have any other numbers.

Regards

-- 
Mladen Gogala
Database Consultant
Tel: (347) 321-1217


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