ESX 4.x VM in orphaned state

Issue: the vm was orphaned and unpingable.
Resolution: Open the datastore browser of the datastore which contains the VM files.
Remove the host from the inventory.
Right click on the cluster which contains the VM and rescan for datastores.
Right click on the .vmx file of the VM in the datastore browser and add to inventory.
Power on the VM.
Caution: It will fail once or twice when you try to add the VM to the inventory but try 2 to 3 times in different resource pools of the cluster if you have more than one resource pool and it will work.
Cause: interrupted power to the host or cluster will make the host lose its connection to the storage improperly and when the hosts are powered on we should always right click on the host and rescan for datastores and such issues can then be avoided.

Unable to add lun to an ESX (i) 4.x

Issue: Customer is unable to add a lun to an ESX(i) 4.x host.
when customer clicks on add storage and selects the particular lun to be added, chooses the block size and clicks on finish he gets the
Error: -

call hostdatastoresystem.CreateVmfsDatastore" for object on "<CLUSTER>" ESXi "<HOSTNAME>" failed. operation failed, diagnostic report: Unable to create Filesystem, please see VMKernel log for more details.

 

hostd logs below

 Resolution: There was a pre existing partition in the lun which was being presented. Deleted that partition using the fdisk command utility from the vCLI and we were able to successfully present the lun.

vmware kb: 2000454