Downgraded from 6.5 to 6.0 Datastores are now missing

[Admlshak3]

One of the guys on my team was trying to downgrade from 6.5 to 6.0 so we could import this remote host into our main vpshere serverc which is on 6.0u2, as well as reset the root password which was improperly documented at the time of install, so nobody could access it.  The Vm's were all stored to local storage on this server.  During the install he did selected "Install" from the options so the root password would be reset.  However after the restart  we can see the Storage under devices, but there are no datastores showing up after a re-scan and adding a new one only gives the option to format and re partition.  I'd really rather not do this for obvious reasons.  The OS is installed to a SD card and the datastores are on physical disks so he figured the datastores would remain, but just need to be re added.  This was also a fresh install of 6.5 and the servers vmotioned over from a older 5.5 server when this was set up about 6 months ago. Any command line wizardry or options I don't know about that we can use to salvage this situation?

[a_p_]

To get a first overview, please run

partedUtil getptbl /vmfs/devices/disks/...

for all disks listed in this directory, and post the output to a reply post.

André

[continuum]

I doubt that ESXi 6 can handle VMFS-volumes created by 6.5
I highly recommend not to try any stunts and revert back to 6.5.

[a_p_]

continuum​ is right. If the datastores were formatted with the new VMFS6 version, then you need ESXi 6.5 (or recreate the datastores, and restore the VMs from your backup).

Unless you are sure, either watch the VMkernel log via "Alt-F12" while booting the host, or run:

grep -i mismatch /var/log/vmkernel.log

after the host is up.

You'll should find s.th. like:

2017-08-07T ... LVM major version mismatch (device 6, current 5)

for each VMFS6 partition.

André