You'll need to edit the /etc/multipath.conf file to add a blacklist exception for your drives.
QuantaStor now has the ability to enable Multipath I/O through the QuantaStor web user interface. By right mouse clicking on a physical disk that is not configured for multipath (ie it's name may start with sdX but won't start with dm-), then selecting "Multipath Configurator". After the Multi-path Device Configurator screen appears, click the Scan button to populate the drop down, select the drive type that is not in multipath mode and click add. These drives will then be scanned and if multiple paths reach the same drive, they will be configured for Multipath I/O. Sometimes it takes a minute or two to reconfigure these drives. Re-scanning the controller, the Physical Disks, and sometimes logging out and back in is necessary. Once drives are configure as Multipath I/O devices they will no longer show up named as sdX.
When you edit the /etc/multipath.conf look for the section that says "blacklist_exceptions". In there add the SCSI vendor ID and SCSI product ID for the manufacturer of your hard drives.
For example, if you have a device at /dev/sdf you can use the command "sg_inq /dev/sdf" and it will show you the vendor ID in the "Vendor identification: " section and the SCSI product ID in the "Product identification:" section.
After that run 'service multipath-tools restart', then run 'multipath -ll' to see the list of paths.
Be sure to run all of these commands without the quotes.
Once multipathing is properly configured you can then create a storage pool using the device mapper paths.
Please review the link below for additional detail: