Re: chunk size (was Re: Time to deprecate old RAID formats?)

[Michal Soltys <nozo@ziu.info>]

Doug Ledford wrote:
> 
> Well, first I was thinking of files in the few hundreds of megabytes
> each to gigabytes each, and when they are streamed, they are streamed at
> a rate much lower than the full speed of the array, but still at a fast
> rate.  How parallel the reads are then would tend to be a function of
> chunk size versus streaming rate. 

Ahh, I see now. Thanks for explanation.

I wonder though, if setting large readahead would help, if you used larger 
chunk size. Assuming other options are not possible - i.e. streaming from 
larger buffer, while reading to it in a full stripe width at least.

> 
> I'm not familiar with the benchmark you are referring to.
> 

I was thinking about 
http://www.mail-archive.com/linux-raid@vger.kernel.org/msg08461.html

with small discussion that happend after that.