Archive for February, 2011

Extending RDM and VMFS LUN’s

You will find that mapped RDM datastores in virtual compatibility mode cannot be extended simply by a re-scan of the HBA and extending the drive. In this case you will need to shut down the server, make note of the scsi x:y postion, un-map that volume from the virtual machine and re-map it again. This would recreate the descriptor file with the added space.

A simple rescan within your VM OS would show the added space which you can extended using DISKPART or any other tool out there.

RDM’s in physcial compatibility mode can be extended easily without the above steps.

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Changing QLogic FC HBA firmware configuration using vMA on ESXi

In order to manage an ESX or ESXi host using vMA they will need to be added to vMA first:

sudo vifp addserver <servername>

It would ask you for a username and password which would cache in order to run any future remote scripts.

vifptarget –s <servername>

This would let you target a specific ESX/ESXi host

For the list of available parameters for Qla2xxx and Qla4xxx have a look at (Changing HBA parameters in ESXi).

To apply a single or a set of parameters using vMA, use the following syntax:

Example: vicfg-module –s ‘qlport_down_retry=60 ql2xmaxqdepth=64’ qla2xxx

To display parameters set on an HBA use the command: vicfg-module –g qla2xxx

Make sure you reboot the host after making any changes to take effect.

Note: If you apply a single parameter change at a time it would reset all other parameters to default and only apply the last parameter change to the host.

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Host vMotion fails with “source detected that destination failed to resume”

I have searched the internet high and low for some information on this error, the virtual machine fails at 82% during host migration.

No snapshots were attached to the server, however there were a large number of .vmsn files in the root folder. I have had problems backing up that server using vDR because it used to fail on creating the snapshot. Apparently these files are created even though the backup was failing which accumulated over time, files aren’t being marked for deletion.

Going back to vMotion, some of the information recorded on the web is about misconfiguration of VMFS ID’s depending on how you assigned the name to the datastore and how consistent is that name within your virtual environment. ESX assigns a hexadecimal value based on the name you assign to the datastore. For a successful vMotion, each shared datastore should have the same hexadecimal representation on each ESX host and that can be checked by running vdf –h on the console on each host.

The problem was solved by doing a storage vMotion to another shared datastore and then performing host vMotion which worked successfully. There is another way which entails disconnecting the shared datastore and re-mapping it again. I haven’t tried this myself by it worked for some people with similar issue. The latter will cause some downtime since you have to disconnect the LUN and reconnect it again which means shutting down all your effected VM’s.


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First look at RVTools

As stated on the RVTOOL Site, it is a Windows .Net application which interacts with your virtual environment using the latest VI SDK to gather health and resource information about each of the ESX hosts and virtual machines. You can either connect directly to an ESX host or call out your environment via vCentre.

I have come across this tool while trying to find an easy way to examine and release a CD or Floppy Disk if mounted to any of the virtual machines, but this is only few of the many uses for this tool. The new version allows passthrough authentication, so you can use your domain username and password to login and use the tool. It also provides some new command line options.

I would recommend having a look at this tool.


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