The datastore charts contain information about disk usage for datastores. The help topic for each chart contains information about the data counters displayed in that chart. The counters available are determined by the collection level set for vCenter Server.
Space in GB The Space in GB chart displays space usage data counters for datastores.
Space Utilization By File Type The Space Utilization by File Type chart displays space used by virtual disks, swap files, snapshot files, and other virtual machine files on the the datastore.
Space Utilization by Virtual Machine The Space Utilization by Virtual Machine chart displays the amount of space used by the five virtual machines with the most space used on the datastore.
Storage I/O Control Normalized Latency This chart displays the normalized latency in microseconds on the datastore, which is the latency that is monitored by Storage I/O Control to detect congestion on the datastore. This metric computes a weighted response time across all hosts and VMs accessing the datastore. I/O count is used as the weight for the response time. It captures the device level latency and does not include any queuing inside the hypervisor storage stack or inside the VM. It is adjusted for I/O size, meaning that high latencies that are the result of very large I/Os are discounted so as not to make the datastore seem slower than it really is. Data for all virtual machines is combined. This chart will display zero values when Storage I/O Control is disabled.
Storage I/O Control Aggregate IOPs This chart displays the number of I/O operations per second on the datastore, aggregated across all hosts and virtual machines accessing the datastore. The chart displays zero values when Storage I/O Control is disabled.
Storage I/O Control Activity This chart displays the percentage of time during which Storage I/O Control actively controlled the datastore latency.
Average Device Latency per Host This chart displays the average amount of latency on a host device. The chart displays the ten hosts with the highest device latency.
Maximum Queue Depth per Host This chart displays maximum queue depth that hosts are currently maintaining for the datastore. When Storage I/O is enabled, queue depth can change over time when congestion is detected at the array.
Read IOPs per Host This chart displays the per-host disk read rates for a datastore. The chart displays information about the ten hosts with the highest values.
Write IOPs per Host This chart displays the per-host disk write rates for a datastore. The chart displays information about the ten hosts with the highest values.
Average Read Latency per Virtual Machine Disk This chart displays the top ten virtual machine disks with the highest average read latency in milliseconds. Data is not displayed when the virtual machine is powered off.
Average Write Latency per Virtual Machine Disk This chart displays the top ten virtual machine disks with the highest average write latency in milliseconds. Data is not displayed when the virtual machine is powered off.
Read IOPs per Virtual Machine Disk This chart displays the top ten virtual machines with the highest number of read operations. Data is not displayed when the virtual machine is powered off.
Write IOPs per Virtual Machine Disk This chart displays the ten virtual machines with the highest number of write operations. Data is not displayed when the virtual machine is powered off.
Virtual Machine Observed Latency per Datastore This chart displays the average datastore latency as observed by the virtual machines.