QuantaStor LUN Presentation Formats and Changes Across Versions

Subject:

When an iSCSI LUN is presented from a target to the initiator, the initiator can query the target for the identifier of that LUN.  Initiators typically calculate a unique identifier based on that.

Older versions of QuantaStor (4.x) had different presentations of iSCSI LUNs. Because of this, an iSCSI initiator such as VMware ESXi may not recognize a QuantaStor Volume after an new QuantaStor ISO install is done. Device identifiers are calculated differently across initiator manufacturers . The documentation for VMware's device naming methods can be found at Understanding Storage Device Naming ​https://docs.vmware.com/en/VMware-vSphere/6.5/com.vmware.vsphere.storage.doc/GUID-A36810F4-00EC-4EA8-A242-2A0DBBF56731.html .

In the case where a new version of QuantaStor is installed over a previous version and the Storage Volumes are preserved, VMware may not recognize the Storage Volumes and will see them as new devices.

Detail:

The datastore is still present on the Storage Volume and there are two ways to get VMware to access them.

1. Setup QuantaStor "touch" files telling it to use the old naming convention
   1. On startup of the QuantaStor services, if it detects the following files, QuantaStor will use the old naming format for LUNs.
   2. To enable, login via ssh as the qadmin user and become root via "sudo -i"
   3. Run the following commands
      1. mkdir -p /var/opt/osnexus/quantastor/touchfiles/
      2. touch /var/opt/osnexus/quantastor/touchfiles/tf_scst_usn.disable
      3. touch /var/opt/osnexus/quantastor/touchfiles/tf_scst_naa_id.disable
   4. After creating these, restart QuantaStor. The system must reboot.
   5. Note: if another version of QuantaStor is ISO installed over this version, the files will have to be recreated.
2. Create new datastores in ESXi pointing to the QuantaStor Storage Volumes without formatting the datastore
   1. Using ESXi web console, select the device presented by QuantaStor.
   2. Choose New Datastore and name it.
   3. CAUTION.  The next screen defaults to the option to not format the datastore.  Make sure that option is checked.  Formatting the datastore will erase all VMs or data on it.
   4. Once the datastore is created, VMware will recognize the contents and map the VMs to the datastore automatically.