Is there only one Disk-Group on that host? If so it could be an issue on the controller.
If there are multiple Disk-Groups on the host then it is more likely an issue with the Cache-tier or if dedupe is enabled then potentially one Capacity-tier device.
What do you see in vmkernel.log and vobd.log at the time of the latency occurring?
Thanks I will take a look
As TheBobkin , in vSAN 6.5 dedup could be a reason for high latency. If you have the possibility of put the host in maintenance mode and re-create the disk group maybe could resolve the problem.
I don't see how you might get a correlation between dedupe and such issues - for a start, the issue impacted multiple Disk-Groups and vSAN dedupes only per Disk-Group. If you mean device latency/strain from the extra load that enabling/disabling dedupe would do (as it basically has to read and re-write all data), this would also be ruled out from the fact that the graphs indicate the issue occurred over the course of a few minutes not a prolonged duration (and OP likely would have mentioned this if they were performing such activities).
My assumption would still be a controller issue or potentially a knock-on issue on the controller caused by some misbehaving attached device.
I also don't really see how wiping and recreating a Disk-Group would help in anyway - the issue doesn't appear to have been prolonged and thus likely was dealt with by automated functions as opposed to human intervention.