what does realtime means exactly

[therapie]

hello I am monitoring esx perfs cpu and memory and I do not understand the realtime parameter

using ESX 3.5 / VC 2.5 / VI toolkit 1

I understood that real time catch the perfs from the ESX and not the database

but why are they differences between both values

exemples

*

*get-stat -entity $esx -realtime -stat cpu.usage.average = 6.49

**v

***get-stat -entity $esx -stat cpu.usage.average = 16,3

looks like realtime takes the value of cpu 0 and without realtime takes the average between all cpu

*get-stat -entity $esx -realtime -stat mem.usage.average = 36.2

**v

***get-stat -entity $esx -stat mem.usage.average = 30.4

seems like realtime takes 6 % memory more thant without what is this 6% for?

thanks for help

Daniel

*

[LucD]

You are correct, the realtime parameter captures the statistical data that is available on the ESX server.

The ESX server uses a 20 second interval to capture his statistics.

Every +/- 1 minute this data is transferred from the ESX server to the VC.

On the VC the statistical is averaged over the historical intervals.

The default length for Historical Interval 1 is 5 minutes.

That means that the data from HI1 takes about 15 realtime samples to calculate the average.

It is important to look at the interval that is returned by the Get-Stat cmdlet.

I suspect the differences you are seeing come from the different interval lengths and the fact that the values are averages over the interval.

[therapie]

thanks for your answer

seems to be ok for memory

but if I compare the perf chart in VCenter with the results for cpu in vi toolkit

the value I have for realtime correspond to the cpu 0 and the value I have without realtime correspond to the average realtime of the chart

for exemple I have an esx with a saturation of cpu0 but the other ones are very low so cpu 0 100% and the average of cpu is 16% according to the vcenter chart for realtime

and vi toolkit gives me always 100% for realtime cpu ... should be around 16 %

Daniel

[LucD]

With the CPU metrics the Get-Stat cmdlet returns also a property called Instance.

That will say for which CPU the statistical value is.

You are probably only looking at 1 CPU while the VIC gives you the average over all the CPUs.

If you want the average you will have to make the sum in your script.

[therapie]

do you know how I can access this property "instance"?

I tried to find it in get-stat but can not

[LucD]

Something like this for example

Get-Stat -Stat cpu.usage.average -Entity (Get-VMHost <ESX-hostname>) -Realtime | %{
  Write-Host $_.Timestamp $_.Instance $_.Value
}

[therapie]

thanks

this confirm that there is an issue perhaps I should update version of VI toolkit I use V1

here is the result I have instance is not recognised as a property

PS 26/03-09:28 > Get-Stat -Stat cpu.usage.average -Entity $esx -Realtime |select-object timestamp,instance, value

Timestamp instance Value

-

---

-

---

-

---

26/03/2009 08:29:20 10.43

26/03/2009 08:29:00 16.04

26/03/2009 08:28:40 34.11

26/03/2009 08:28:20 10.73

26/03/2009 08:28:00 10.62

26/03/2009 08:27:40 9.36

26/03/2009 08:27:20 13.01

26/03/2009 08:27:00 30.59

26/03/2009 08:26:40 27.93

26/03/2009 08:26:20 14.71

and here is the result of get member no trace of instance property

PS 26/03-09:32 > Get-Stat -Stat cpu.usage.average -Entity $esx -Realtime | get-member * -force

TypeName: VMware.VimAutomation.Client20.FloatSampleImpl

Name MemberType Definition

-

---

-

---

-

---

pstypenames CodeProperty System.Collections.ObjectModel.Collection`1[[System.String, mscorlib, Version=2.0.0.0, ...

psadapted MemberSet psadapted {Value, Timestamp, MetricId, Unit, Description, Entity, get_Value, get_Timest...

psbase MemberSet psbase {Value, Timestamp, MetricId, Unit, Description, Entity, get_Value, get_Timestamp...

psextended MemberSet psextended {MSDN}

psobject MemberSet psobject {Members, Properties, Methods, ImmediateBaseObject, BaseObject, TypeNames, get...

Equals Method System.Boolean Equals(Object obj)

GetHashCode Method System.Int32 GetHashCode()

GetType Method System.Type GetType()

get_Description Method System.String get_Description()

get_Entity Method VMware.VimAutomation.Types.VIObject get_Entity()

get_MetricId Method System.String get_MetricId()

get_Timestamp Method System.DateTime get_Timestamp()

get_Unit Method System.String get_Unit()

get_Value Method System.Single get_Value()

set_Description Method System.Void set_Description(String value)

set_Entity Method System.Void set_Entity(VIObject value)

set_MetricId Method System.Void set_MetricId(String value)

set_Timestamp Method System.Void set_Timestamp(DateTime value)

set_Unit Method System.Void set_Unit(String value)

ToString Method System.String ToString()

Description Property System.String Description {get;set;}

Entity Property VMware.VimAutomation.Types.VIObject Entity {get;set;}

MetricId Property System.String MetricId {get;set;}

Timestamp Property System.DateTime Timestamp {get;set;}

Unit Property System.String Unit {get;set;}

Value Property System.Single Value {get;}

MSDN ScriptMethod System.Object MSDN();

[LucD]

Yes, you should go to VITK v1.5.

The Instance property is new in that release.