VMware datastore capacity

The VmwareCollector emits a multi-instance resource for each datastore a HostSystem mounts, alongside the performance counters it already collects. The values come from Datastore.summary, a property on the managed object, rather than from vCenter’s PerformanceManager — so capacity numbers reflect what vCenter reports at collection time, not a 5-minute averaged sample.

Datastore data is collected automatically for every host imported by the VMware requisition handler, scoped to the datastores that host mounts. A datastore mounted by multiple hosts is collected once per host, under each host’s resource tree.

When this group runs

The shipped default-HostSystem6 and default-HostSystem7 collections include a <vmware-group> with resourceType="vmwareDatastoreCapacity". When VmwareCollector iterates a host’s configured groups, that resource type triggers the datastore dispatch instead of a PerformanceManager query. Removing the group from a custom collection disables datastore collection for hosts using that collection.

The group is only valid inside HostSystem collections. If it appears in a VirtualMachine collection (or any non-HostSystem managed entity), the collector logs a warning and skips it.

Resource layout

Per host:

share/rrd/snmp/{nodeId}/vmwareDatastoreCapacity/{datastoreMoid}/
  DsCapacity.rrd  DsFreeSpace.rrd  DsUsed.rrd  DsUsedPct.rrd
  DsUncommitted.rrd  DsOvercommitted.rrd  DsAccessible.rrd  DsMultiHost.rrd
  strings.properties   (DsType, DsUrl, vmwareDatastoreCapacityName)

The resource type is registered globally via ${OPENNMS_HOME}/etc/resource-types.d/vmware-datastore-resource.xml. Graphs are defined in ${OPENNMS_HOME}/etc/snmp-graph.properties.d/vmware-datastore-graph.properties.

Numeric attributes (gauges)

Attribute Description

Attribute	Description
capacity	Total size of the datastore in bytes, as reported by vCenter.
freeSpace	Free space in bytes.
used	Computed as `capacity - freeSpace`.
usedPct	Integer percent of capacity in use (0-100). Returns `0` if `capacity` is `0`.
uncommitted	Bytes promised by thin-provisioned virtual disks but not yet written. Coerced to `0` when vCenter does not report a value.
overcommittedBytes	Computed as `max(0, used + uncommitted - capacity)`. Non-zero values indicate the datastore is at risk if thin-provisioned VMs grow into their full provisioned size.
accessible	`1` if vCenter reports the datastore as accessible at collection time, `0` otherwise.
multipleHostAccess	`1` if the datastore is mounted by more than one host, `0` otherwise. Coerced to `0` if vCenter does not report a value.

capacity

Total size of the datastore in bytes, as reported by vCenter.

freeSpace

Free space in bytes.

used

Computed as capacity - freeSpace.

usedPct

Integer percent of capacity in use (0-100). Returns 0 if capacity is 0.

uncommitted

Bytes promised by thin-provisioned virtual disks but not yet written. Coerced to 0 when vCenter does not report a value.

overcommittedBytes

Computed as max(0, used + uncommitted - capacity). Non-zero values indicate the datastore is at risk if thin-provisioned VMs grow into their full provisioned size.

accessible

1 if vCenter reports the datastore as accessible at collection time, 0 otherwise.

multipleHostAccess

1 if the datastore is mounted by more than one host, 0 otherwise. Coerced to 0 if vCenter does not report a value.

String attributes

Attribute Description

Attribute	Description
name	Display name of the datastore (also used as the resource label).
type	Datastore type: `VMFS`, `NFS`, `NFS41`, `vsan`, `VVOL`, etc.
url	Datastore URL (for example, `ds:///vmfs/volumes/<uuid>/`).

name

Display name of the datastore (also used as the resource label).

type

Datastore type: VMFS, NFS, NFS41, vsan, VVOL, etc.

url

Datastore URL (for example, ds:///vmfs/volumes/<uuid>/).