VMware has admitted that its guidance about the hardware needed to run its vSAN virtual storage arrays has been wrong for years.
“Hardware guidance for vSAN has historically been derived from synthetic testing,” Product Marketing Engineer Pete Koehler wrote last week, explaining that VMware used that approach because it allowed tests for performance “under the most extreme circumstances.”
Koehler said VMware has since revisited its testing regime because, “While useful, synthetic tests do not reflect the characteristics of real world workloads and the behavior of the storage system.” His team therefore “pored over telemetry data gathered from thousands of vSAN clusters running all types of production workloads” and found vSAN clusters use “much less RAM than expected” and “may use fewer CPU resources than expected.”
VMware’s latest guidance for hardware used in vSANs therefore has lower minimum specs for “ReadyNodes” – the storage-centric servers used in virtual storage arrays – a welcome change at a time when increasing memory prices are making servers more expensive. The guidance could also mean vSAN users can get away with using fewer ReadyNodes.
Koehler also pointed to the potential for vSAN designs based on VMware’s new recommendations to consume less energy, and therefore reduce cooling requirements.
“The potential to meet your capacity and performance requirements with a minimal footprint may mean more optimal placement of hosts in racks to reduce network resource consumption, and delay potential network upgrades,” he wrote.
It’s good news for VMware parent company Broadcom, which wants buyers to go all-in on its Cloud Foundation private cloud stack for virtual compute, networks, and storage, instead of using external arrays. More modest ReadyNode specs, and cheaper boxes, may mean more buyers find the numbers add up for Cloud Foundation even after Broadcom’s licensing changes saw their bills increase.
VMware’s new view of vSAN may also help it combat rivals who have marketed their wares as offering virtual storage under cheaper licenses, just one of the many skirmishes in the revitalized virtualization market. ®