And according to these messages, probably you run ot of space on datostore named - FreeNAS-MAIN
2018-03-27T14:08:32.146Z info hostd[ECC1B70] [Originator@6876 sub=Hostsvc.VmkVprobSource] VmkVprobSource::Post event: (vim.event.EventEx) {
--> key = 70399,
--> chainId = 791707782,
--> createdTime = "1970-01-01T00:00:00Z",
--> userName = "",
--> datacenter = (vim.event.DatacenterEventArgument) null,
--> computeResource = (vim.event.ComputeResourceEventArgument) null,
--> host = (vim.event.HostEventArgument) {
--> name = "vmhost6",
--> host = 'vim.HostSystem:ha-host'
--> },
--> vm = (vim.event.VmEventArgument) null,
--> ds = (vim.event.DatastoreEventArgument) {
--> name = "FreeNAS-MAIN",
--> datastore = 'vim.Datastore:58768d13-263d8429-65a7-a0369f1464a8'
--> },
--> net = (vim.event.NetworkEventArgument) null,
--> dvs = (vim.event.DvsEventArgument) null,
--> fullFormattedMessage = <unset>,
--> changeTag = <unset>,
--> eventTypeId = "esx.problem.scsi.device.thinprov.atquota",
--> severity = <unset>,
--> message = <unset>,
--> arguments = (vmodl.KeyAnyValue) [
--> (vmodl.KeyAnyValue) {
--> key = "1",
--> value = "naa.6589cfc000000105b9d5a244d16123ac"
--> },
--> (vmodl.KeyAnyValue) {
--> key = "2",
--> value = (vim.event.DatastoreEventArgument) {
--> name = "FreeNAS-MAIN",
--> datastore = 'vim.Datastore:58768d13-263d8429-65a7-a0369f1464a8'
--> }
--> }
--> ],
--> objectId = "58768d13-263d8429-65a7-a0369f1464a8",
--> objectType = "vim.Datastore",
--> objectName = "FreeNAS-MAIN",
--> fault = (vmodl.MethodFault) null
