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extend clustered disk

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Ralf Seefeldt
Valued Contributor

extend clustered disk



I have a problem extending a disk for two ESX 4.1.0 virtual machines running RedHat

The config is:


2 lefthand provide storage

2 ESX host - beseides others - each one VM client. Lets call them M1 and M2

  M2 is hot stand by. M2 sees the disks but does not activite the VGs as long as M1 runs. The switch to M2 woud be


Both virtual machines can access the provided disks.


Disks had been cluster aware in ESX in the original configuration.


Now I had to extend the disks, starting at the lefthands, then the ESX Server and the VMs.

To extend the disks in the vSphere GUI for the VM failed until the cluster awarenes (disks can be accessed by VMs from different ESX Servers) had been disabled.

All disks are thik provisioned.

In vSphere | ... | browse Datastore, the disks can not be inflated. Thus, they seem to be eagerzeroed. On the other hand, VMware writes, that extending a eagerzeroed disk, the extended part will be lazyzeroed.

I know, that there are some CLI comands too, but I don't know them. I don't even know whether the ESX license allows to login to the ESX by ssh/CLI


Then, after starting M1 and its applications, M2 refused to boot. It could not get hold of the disks as they are said to be blocked.


Now, the VM M2 seems to be unable to start as long as M1 is up. I did not verify, that M2 will boot when M1 is shut down becauce my downtime was way over, when I had restarted M1 and all its applications.


So, my question is how can I get the disks enabled for both VMs again?


Any hint will be greately appreciated as I am relatively new to ESX.

As it is christmas time, I may not be able to answer in time to your questions or suggestions.


Bye & have some relaxing holiday




Ralf Seefeldt
Valued Contributor

Re: extend clustered disk

Hi all, meanwhile I figured out the answer. Extending a disk from vSphere removes the eagerzeroed status of a disk. It has to be reset. As this is a ESX testlicence, that functionality is not present in vSphere and thos, the check looks just fine. I have to log in on the cli and execute vmkfstools -k to convert the thick, zeroed disk to a thick, eagerzeroed disk. Bye Ralf