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Performance alarms are made to let you know when your virtual infrastructure shows poor performance.
Datastore Highest Latency shows highest latency value across all datastores used by the host.
Host disk write latency shows average amount of time that a write to the host disk takes.
CPU bottleneck for a host contains Average CPU Ready metrics which shows average CPU Ready value for all VMs on the host.
Full list monitored metrics is provided here
. Please review.
Permissions and security groups are described here