Re: RAID0 performance question

["JaniD++" <djani22@dynamicweb.hu>]

Hello,

> > > > > But the cat /dev/md31 >/dev/null (RAID0, the sum of 4 nodes) only
> > > > > makes ~450-490 Mbit/s, and i dont know why....
> > > > >
> > > > > Somebody have an idea? :-)
> > > >
> > > > Try increasing the read-ahead setting on /dev/md31 using 'blockdev'.
> > > > network block devices are likely to have latency issues and would
> > > > benefit from large read-ahead.
> > >
> > > Also try larger chunk-size ~4mb.
> >
> > Ahh.
> > This is what i can't do. :-(
> > I dont know how to backup 8TB! ;-)
>
> Maybe you could use your mirror!?

I have one idea! :-)

I can use the spare drives in the disknodes! :-)

But i don't know exactly what to try.
increase or decrease the chunksize?
In the top layer raid (md31,raid0) or in the middle layer raids (md1-4,
raid1) or both?

Can somebody help me to find the performance problem source?

Thanks,
Janos


>
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> Al