Do I choose the PVSCSI or LSI Logic virtual adapter on ESX 4.0 for non-IO intensive workloads? I thought that the question about using or not VMware Paravirtual adapter was solved with the vSphere 4 Update 1 and the announce that VMware has officialy support PVSCSI on boot disks. For me it was clear that I was going to use only this adapter for newly created VMs an those with LSI logic were on plan to be migrated. Sooner or later.
As I already blogged about the PVSCSI adapter greatly improves the throughput for heavy I/O workloads and and that also it consumes less CPU.
Use PVSCSI or not
But then there was an interresting KB article from VMware which says that “it depends on your workload“…. 😎
They've done actualy some deep testing on that and the experiment results show that:
PVSCSI greatly improves the CPU efficiency and provides better throughput for heavy I/O workloads. For certain workloads, however, the ESX 4.0 implementation of PVSCSI may have a higher latency than LSI Logic if the workload drives low I/O rates or issues few outstanding I/Os.
They also have a solution for taking a decision whether Yes or Not use this adapter:
So you'd have to go and test the IOPS for those VM's that you think that should be migrated or not….
UPDATE: Scott Sauer has posted a “Deep dive” explanation on his blog. Make sure to check this out…
Source: VMware KB