Device naa.xxxxx123 performance has deteriorated. I/O latency increased from average value of 1832 microseconds to 19403 microseconds
ESXi
To get the lun level device performance statistics data use the esxtop utility. Refer to this article for more information: Using esxtop to identify storage performance issues (1008205)
High device latency
It is useful to consider a 4-dimensional framework to characterize the latency.
1) Magnitude: How high are the spikes in DAVG?
2) Duration: How long does each spike last?
3) Frequency: What sort of pattern is exhibited by the date / time stamps?
4) Spread: How widespread are the events?
Magnitudes of limited amount (say, for example, 20-30ms) for durations of only a few seconds, on an occasional frequency, on a small subset of datastores, is a vastly different situation than, say, magnitudes of multiple seconds, for durations of multiple minutes. The latter situation could be perceived by most VMs as a storage outage, and Linux machines, for example, can turn their disks read only as a protective measure.