ShocKNetworK Blog

A similar situation occurs when you set the SPC-2 flag on your EMC Symmetrix Storage Array.

This procedure is used to allow you to change the Host Mode setting/director flags on your array and make all of the VMFS3 volumes visible again.

1. Stop the running VMs on all the ESX servers.

2. Change the Host Mode/Director flags on the Storage Array – now when you rescan, you will see snapshot LUN mentioned in /var/log/vmkernel.

3. Enable LVM Resignaturing on the first ESX server => set LVM.EnableResignature to 1.

-log to the ESX with VI client

-select the configuration tab

-select the Advanced setting option

-select the LVM section

-make sure that the fourth and last option allowresignaturing is set to 1.

-save the change

-select storage adapter

-select rescan adapter

-leave the default option and proceed

-you should now be able to see the VMFS

4. Disable LVM Resignaturing

-log to the ESX with VI client

-select the configuration tab

-select the Advanced setting option

-select the LVM section

-make sure that the fourth and last option allowresignaturing is set to 0.

-save the change

5. No snapshot messages should now be visible in the /var/log/vmkernel.

6. Re-label the volume

-log to the ESX with VI client

-select Datastores view in inventory view

-select the datastore, right click, select remove to remove the old label as this is associated with the old UUID of the volume

-select Hosts & Clusters view instead of Datastores view

-in the summary tab, you should see the list of datastores

-click in the name field for the volume in question and change it to the original name – you now have the correct original label associated with the resignatured volume

7. Now rescan from all ESX servers

8. Re-register all the VMs

-Because the VMs will be registered against the old UUID, you will need to re-register them in VC.

-log to the ESX with VI client

-select the configuration tab

-select Storage(SCSI, SAN & NFS)

-double-click on any of the datastores to open the Datatstore browser

-navigate to the .vmx file of any of the VMs by clicking on the folders

-right click, select ‘add to inventory’

9. Remap any RDMs

-If you a VM which uses an RDM, you will have to recreate the mapping.

-the problem here is that you may not be able to identify which RDM is which if you used multiple ones.

-if they are different sizes, then this is ok – you should be able to map them in the correct order by their size

-make a note of the sizes of the RDMS and which VMs they are associated with before starting this process

-make a note of the LUN ID before starting this process too – you may be able to use this to recreate the mapping

-if they are all the same size, this is a drag since you will have to map them and boot the VM, and then check them

-if you do not use RDMs, you can ignore this step

10. Powering on the VMs

-start the VM, reply yes if prompted about a new UUID

-if any of the VMs refer to missing disks when they power up, check the .vmx file and ensure that the scsi disk references are not made against the old uuid instead of the label.

-if any of the VMs refer to missing disks when they power up, check the .vmx file and ensure that the scsi disk references are not made against the old label instead of the new label if you changed it.

11. Repeat steps 3 thru 10 for all subsequent ESX servers that are still seeing snapshot volumes.

-if all ESX servers share the same volumes, then this step will not be necessary]]>