> Le 8 août 2017 à 15:24, FERNANDO FREDIANI <fernando.fredi...@upx.com> a écrit 
> :
> That's something on the way RAID works, regardless what most 'super-ultra' 
> powerfull hardware controller you may have. RAID 5 or 6 will never have the 
> same write performance as a RAID 10 o 0 for example. Writeback caches can 
> deal with bursts well but they have a limit therefore there will always be a 
> penalty compared to what else you could have.

Hardware RAID5/6 can have better performance with quite common hardware that 
software RAID0. I have seen many time on on even old servers that write latency 
(hitting the cache) was smaller that read latency that was going directly to 
the disk. I'm not talking about 'super-ultra' powerfull hardware. An HP Smart 
Array P440ar with 2 GB flash is sell at 560€, public price. Not cheap, but not 
ultra powerfull.

It's now a matter of identifying the bootle neck, and how much money you can 
throw at it.
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