vsphere-esxi-vcenter-server-55-storage-guide

Chapter 19 Working with Virtual SANCommandesxcli vsan network listesxcli vsan storage listesxcli vsan cluster getDescriptionVerify which VMkernel adapters are used for Virtual SAN communication.List storage disks that were claimed by Virtual SAN.Get Virtual SAN cluster information.Local SSDs Are Unavailable for Use with Virtual SANWhen a local SSD disk is used as a Flash Read Cache resource or is formatted as VMFS, it becomesunavailable for Virtual SAN.ProblemA local SSD disk does not appear on the list of disks to be claimed by Virtual SAN.CauseThis happens when you format a local SSD disk as VMFS or use it as a Flash Read Cache resource. FlashRead Cache and Virtual SAN are mutually exclusive consumers of SSD disks and configure SSDsdifferently. They cannot share the same SSD disk. Virtual SAN cannot share the SSD disk with any other filesystems including VMFS.SolutionIf you need to claim an SSD disk for Virtual SAN, make sure that the disk is unformatted with VMFS and isnot used for Flash Read Cache.• Avoid formatting the SSD disk with VMFS during ESXi installation or Auto Deploy. For information,see “Preventing SSD Formatting During Auto-Partitioning,” on page 170.• If SSD that you plan to use with Virtual SAN is already formatted with VMFS, remove the VMFSdatastore. See “Remove VMFS Datastores in the vSphere Web Client,” on page 146.• If SSD is used as a Flash Read Cache resource, remove the Flash Read Cache resource. After the FlashRead Cache resource is removed and the SSD disk is erased, the disk becomes available for VirtualSAN. See “Remove Virtual Flash Resource,” on page 208.In addition, a local SSD might be unavailable because ESXi cannot recognize it. For information see, “LocalSSDs Are Undetectable,” on page 171Virtual SAN Configuration on an ESXi Host Might FailIn certain circumstances, the task of configuring Virtual SAN on a particular host might fail.ProblemAn ESXi host that joins a Virtual SAN cluster fails to have Virtual SAN configured.CauseIf a host does not meet hardware requirements or experiences other problems, Virtual SAN might fail toconfigure the host. For example, insufficient memory on the host might prevent Virtual SAN from beingconfigured.Solution1 Place the host that causes the failure in Maintenance Mode.2 Move the host out of the Virtual SAN cluster.3 Resolve the problem that prevent the host to have Virtual SAN configured.4 Exit Maintenance Mode.VMware, Inc. 191