Does a raid controller use cache in JBOD mode?

Solution 1:

All on-board caches are completely bypassed in JBOD mode. If you really need to use them you might want to look at a single-disk RAID0 config, which is unsupported but works with S2D as long as you patch "RAID" -> "SAS" BusType in registry.

https://livevirtually.net/2014/06/27/configuring-hp-smart-array-p420i-io-controller-for-vsan/

(That's for VMware VSAN but hardware config and approach are same...)

https://www.starwindsoftware.com/blog/resolving-enable-clusters2d-bus-type-support-issue-on-some-storage-controllers

In general if you want to get some use out of the hardware you already own you'll have to use software-defined storage stack with zero dependency on underlying hardware. Look at HPE VSA and StarWind vSAN, both have free versions to experiment with.

https://h20392.www2.hpe.com/portal/swdepot/displayProductInfo.do?productNumber=VSA1TB-S

https://www.starwindsoftware.com/starwind-virtual-san-free

What you normally do - you combine local hardware RAID with inter-node replication for performance and higher level of fault tolerance. This approach is widely used by HPE VSA and SimpliVity (now part of HPE as well) HCI.

https://www.simplivity.com/blog/2016/02/anatomy-simplivity-hyperconverged-infrastructure/