Virtual Volumes change quite a lot of things. One of these is how your storage volumes are actually connected. This change is necessitated for two reasons:
- Scale. Traditional ESXi SCSI limits how many SCSI devices can be seen at once. 256 in 6.0 and earlier and 512 in 6.5. This is still not enough when every virtual disk its own volume.
- Performance. Virtual Volumes are provisioned and de-provisioned and moved and accessed constantly. If every time one of these operations occurred a SC SI rescan was required, we would see rescan storms unlike this world has ever witnessed.
So VMware changed how this is done. Continue reading Virtual Volumes: VVol Bindings Explained