Performance Measuring: Discovers/sec.

Performance_Measuring__Discovers_sec._1_Rule (Rule)

Knowledge Base article:

Management Pack

Summary
This counter measures the number of DHCP Discover (DHCPDiscover) messages received per second by the DHCP 2000 Server from clients. A DHCP Discover message is sent by a DHCP client to the DHCP 2000 Server to obtain an IP address lease from the server. Typically, this counter is used to indicate when there is a sudden or unusual increase in the number of clients attempting to initialize and obtain an IP address lease.

Causes
A large number of clients attempting to initialize and obtain an IP address lease from the DHCP 2000 Server at the same time can trigger this alert. This might be a normal occurrence, such as when a large number of users log on when the workday begins.

Resolutions
Compare the value for the Discovers/sec counter with the values of the Offers/sec counter. The Offers/sec counter measures the number of DHCP Offer (DHCPOffers) messages sent per second by the DHCP 2000 Server to clients, offering the lease of an IP address to a DHCP client when it starts on the network. The values for Discovers/sec and Offers/sec should be about the same. If a discrepancy exists: Determine whether the scope is full. If it is full, modify the scope size to accommodate the number of existing clients. Investigate whether a problem exists on the client side.

Element properties:

Target	Microsoft.Windows.Server.DHCP.Microsoft_Windows_2000_DHCP_Servers_Installation
Category	PerformanceCollection
Enabled	True
Instance Name	DHCP Server
Counter Name	Discovers/sec
Frequency	900
Alert Generate	False
Remotable	True
Comment	Mom2005ID='{18D1BF5A-521C-4933-AB50-5759FAD08EA8}';MOM2005ComputerGroupID={37B5AB26-6DE0-11D3-945C-0090275A5879}

Member Modules:

ID	Module Type	TypeId	RunAs
_70D321D8_8515_48E1_B481_F095C7D6C786_	DataSource	System.Mom.BackwardCompatibility.Performance.FilteredDataProvider	Default
CollectPerfData	WriteAction	Microsoft.SystemCenter.CollectPerformanceData	Default
CollectPerfDataWarehouse	WriteAction	Microsoft.SystemCenter.DataWarehouse.PublishPerformanceData	Default
GenerateAlert	WriteAction	System.Mom.BackwardCompatibility.AlertResponse	Default

Source Code:

<Rule ID="Performance_Measuring__Discovers_sec._1_Rule" Target="Microsoft.Windows.Server.DHCP.Microsoft_Windows_2000_DHCP_Servers_Installation" Enabled="true" ConfirmDelivery="false" Comment="Mom2005ID='{18D1BF5A-521C-4933-AB50-5759FAD08EA8}';MOM2005ComputerGroupID={37B5AB26-6DE0-11D3-945C-0090275A5879}">

  <Category>PerformanceCollection</Category>

  <DataSources>

    <DataSource ID="_70D321D8_8515_48E1_B481_F095C7D6C786_" Comment="{70D321D8-8515-48E1-B481-F095C7D6C786}" TypeID="MomBackwardCompatibility!System.Mom.BackwardCompatibility.Performance.FilteredDataProvider">

      <ComputerName>$Target/Host/Property[Type="WindowsLibrary!Microsoft.Windows.Computer"]/NetworkName$</ComputerName>

      <CounterName>Discovers/sec</CounterName>

      <ObjectName>DHCP Server</ObjectName>

      <Frequency>900</Frequency>

      <Expression/>

    </DataSource>

  </DataSources>

  <WriteActions>

    <WriteAction ID="GenerateAlert" TypeID="MomBackwardCompatibility!System.Mom.BackwardCompatibility.AlertResponse">

      <AlertGeneration>

        <GenerateAlert>false</GenerateAlert>

      </AlertGeneration>

      <InvokerType>1</InvokerType>

    </WriteAction>

    <WriteAction ID="CollectPerfData" TypeID="SystemCenterLibrary!Microsoft.SystemCenter.CollectPerformanceData"/>

    <WriteAction ID="CollectPerfDataWarehouse" TypeID="DataWarehouseLibrary!Microsoft.SystemCenter.DataWarehouse.PublishPerformanceData"/>

  </WriteActions>

</Rule>