Exam 5V0-21.19 topic 1 question 23 discussion

On a normal basis you should not see resyncs occurring in your vSAN environment. It makes more sense that your write cache is sized too small (even though all flash) and can't destage fast enough to keep up with the application.

I believe D is the answer. If your caching tier can't drain fast enough you would see performance issues.

B is correct

B is corrct answer: https://kb.vmware.com/s/article/2150101

I think B is the correct answer.

I think B. I would always look first for latencies (and congestions). A - high recovery write IOPS show you that something has happened in the cluster and data is recovered to cache or capacity SSDs. big failures could influence the performance... C - the metric "read cache read IOPS" doesn't exist. I only know the local client cache hit IOPS metric. D - low write buffer free percentage normally should not influence the performance in an all-flash cluster. colder write buffer data will get destaged from cache to capacity SSDs.

agree with this, B sounds as the most util answer

I belive that B is the right answer: You can reduce the number of IOPS used to perform resynchronization on disk groups in the vSAN cluster. Resynchronization throttling is a cluster-wide setting, and it is applied on a per disk group basis. If VMs are not responding due to latency caused by resynchronization, you can throttle the number of IOPS used for resynchronization. Consider resynchronization throttling only if latencies are rising in the cluster due to resynchronization, or if resynchronization traffic is too high on a host. https://docs.vmware.com/en/VMware-vSphere/7.0/com.vmware.vsphere.vsan-monitoring.doc/GUID-8D81FCF6-AC9A-4C2C-A8AC-DE50B9965054.html