Home > Servers > PowerEdge and VMware > White Papers > Dell PowerEdge XR4000 Deployment in a vSAN 2.1 Configuration > Recovery/Reinstall of the nano sled and server sleds
As noted in the earlier sections, the XR4000w nano sled and the XR4510c server sleds shipped from Dell factories are pre-installed with a Dell customized version of VMware ESXi, according to customer preference. For the XR4000z server sleds, the Dell BMC (aka iDRAC) provides various options to boot from an ISO image like the general options available for PowerEdge servers. This section describes how to re-install VMware ESXi on a nano sled explicitly because the nano sled does not have a server BMC to manage. Dell provides the RASR utility to help re-install/recover VMware ESXi on a PowerEdge XR4000w. For details about using RASR for PowerEdge XR4000w, see Chapter 6 of the XR4000w installation and service manual.