On Tue, Aug 8, 2017 at 9:16 AM, Fabrice Bacchella <fabrice.bacchella@orange.fr> wrote:

> Le 8 août 2017 à 04:08, FERNANDO FREDIANI <fernando.frediani@upx.com> a écrit :

> Even if you have a Hardware RAID Controller with Writeback cache you will have a significant performance penalty and may not fully use all the resources you mentioned you have.
>

Nope again,from my experience with HP Smart Array and write back cache, write, that goes in the cache, are even faster that read that must goes to the disks. of course if the write are too fast and to big, they will over overflow the cache. But on todays controller they are multi-gigabyte cache, you must write a lot to fill them. And if you can afford 40Gb card, you can afford decent controller.

The last sentence raises an excellent point: balance your resources. Don't spend a fortune on one component while another will end up being your bottleneck. 
Storage is usually the slowest link in the chain. I personally believe that spending the money on NVMe drives makes more sense than 40Gb (except [1], which is suspiciously cheap!)

Y.
[1] http://a.co/4hsCTqG




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