Archive for April 19, 2013

Re-Register to vCenter Server using Update Manager Utility

Re-Register to vCenter Server using Update Manager Utility

It is necessary to re-register vCenter Server from Update Manager, for example when you change IP Address, Hostname or Certificate of vCenter Server. When you get an error message like below, then you know that you will need to re-register vCenter Server from Update Manager.

There was an error connection to VMware vSphere Manager


When Update Manager is installed, it installs VMwareUpdateManagerUtility under  C:\Program Files (x86)\VMware\Infrastructure\Update Manager folder.

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Replace vCenter Server Certificate

Replace vCenter Server Certificate

vCenter server uses an automatically generated self-signed certificate after the installation. As with ESXi Server, this may not be desirable in some environment and requires use of a CA signed certificate.

As you may be aware when you access vCenter for the first time using vSphere Client or vSphere Web Client, you will receive a certificate warning message as the certificate vCenter uses is not signed by a known CA.

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Replace ESXi Certificate

Replace ESXi Certificate

The ESXi host uses automatically generated certificates that are created as part of the installation process. These certificates are unique and make it possible to begin using the server, but they are not verifiable and they are not signed by a trusted, well-known certificate authority (CA).

Using default certificates might not comply with the security policy of your organization. If you require a certificate from a trusted certificate authority, you can replace the default certificate.

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Configure Bulk Licensing

Bulk Licensing Feature of vSphere is especially useful when ESXi servers are deployed by AutoDeploy. As there is not option to specify the license key via Host Profile, Administrator must manually attach license to ESXi Servers.

Bulk Licensing allows administrator to use pre-defined license keys to ESXi server automatically including AutoDeployed ESXi server.

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Create a custom ESXi Firewall service

ESXi Server has a built-in Firewall to protect your ESXi Server.
There are pre-defined services (source and destination TCP/UDP Port) that you can configure via vSphere Client or CLI, such as permitting or restricting SSH from specified IP Address or Network. These pre-defined services should be sufficient for most of environment.
However there may be a case that you wish to create a custom service, for example when you install a third-party plugin and it uses TCP/UDP that is not defined in the pre-defined list.

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Configuring Network Coredump to vSphere ESXi Dump Collector

In case of ESXi crash, ESXi Server keeps memory dump in local file system for analysis. You can configure Network Coredump to make ESXi server to send memory dump to vSphere ESXi Dump Collector.

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Configuring Syslog in ESXi and vSphere Syslog Collector

Syslog in ESXi sever is critical feature that need to be configured properly in order to monitor and troubleshoot vSphere environment efficiently. By default, ESXi server keeps all logging related information on its scratch partition and that will be removed on every restart of ESXi Server. Thus if your ESXi server crashed for whatever the reason, you have no way to find out what have been happening on the ESXi server. ESXi server supports syslog for a remote log collection, but you will need to configure this manually, or using Host Profile to push this configuration.

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Objective 1.2 – Manage Storage Capacity in a vSphere Environment

Objective 1.2 – Manage Storage Capacity in a vSphere Environment


Identify storage provisioning methods

vSphere support several Storage provisioning methods

VMDK based

  • Thin
  • Thick – Lazy Zero
  • Thick – Eager Zero


  • Physical mode
  • Virtual Mode

I have already posted about VMDK disk provision types in here.

I have already posted about RDM in here

Identify available storage monitoring tools, metrics and alarms

vSphere comes with several monitoring tools for Storage including Performance tab in vSphere Client.

Here are the some of the metrics and corresponding (R)ESXTOP metric that you should be aware of

  • Device Command Latency (DAVG/cmd)
  • Kernel Command Latency (KAVG/cmd)
  • Virtual Machine Latency (GAVG/cmd = DAVG/cmd + KAVG/cmd)
  • Device Queue
  • LUN Queue
  • Number of Aborted disk Command(ABRTS/s)
  • Number of disk Command issue (ACTV)
  • Number of Command in Queue (QUED)
  • Read/Write Rate (READs/s, WRITEs/s, MBREAD/s, MBWRTN/s)

Skills and Ability

Apply space utilization data to manage storage resources 

Provision and manage storage resources according to Virtual Machine requirements

Understand interactions between virtual storage provisioning and physical storage provisioning 

Apply VMware storage best practices 

Configure Datastore Alarms

Analyze Datastore Alarms and errors to determine space availability 

Configure Datastore Clusters    Send article as PDF   

Configuring RDM

RDM provides a direct access to storage system to VM.
There are 2 type of RDMs.

  • Virtual mode
  • Physical mode

With Virtual mode, you can still take advantage of vSphere features such as snapshot and FT. For MSCS in vSphere there is a configuration guide available from VMware. I am planning to blog about this later.

Physical mode is required when you want to do clustering with a physical server or VM needs to do SAN maintenance tasks.

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