[ovirt-users] Good practices

Fabrice Bacchella fabrice.bacchella at orange.fr
Tue Aug 8 13:48:54 UTC 2017


> Le 8 août 2017 à 15:24, FERNANDO FREDIANI <fernando.frediani at 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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