Cannot find the 2nd datastore after upgrading ESXi 3.5

Question

I have an ESXi server (version 3.5) with about 60 VMs. It has 2 hard disks, each of which is regarded as a datastore.

After upgrading through 'VMware Infrastructure Update' tool(still staying with 3.5 instead of 4.0) and a reboot, I can only see the 1st datastore. Hence many VMs are, now, inaccessible.

I wonder how I can get the 2nd datastore back. I am sorry, but I did't have the 2nd datastore backuped before.

BTW, I am still thinking of upgrading directly to version 4.0 to see if it can fix the driver problem. How about that?

UPDATE: My updating to version 4.0 failed with the following error message on the stage of 'Host Compatibility Check':
The boot device layout on the host does not support upgrade.

Answer 1

1. Set Configuration->Advanced Settings->LVM->EnableResignature to 1;
2. Configuration->Storage Adapters->Rescan;
3. Then you can find your original datastore in Configuration->Storage;
4. Set Configuration->Advanced Settings->LVM->EnableResignature to 0;

Since you've changed the identifications of your datastores, you have to add your VMs back to your inventory manually.

via 'VMFS Volume Resignaturing' section of
http://www.vmware.com/pdf/vi3_35/esx_3/r35/vi3_35_25_san_cfg.pdf