The storage troubleshooting topics provide solutions to potential problems that you might encounter when using vSphere in different storage environments that include SAN, vSAN, or Virtual Volumes. Resolving SAN Storage Display ProblemsWhen you use the vSphere Web Client to display Fibre Channel SAN or iSCSI storage devices, you might not be able to see all devices available to your host. A number of troubleshooting tasks exist that you can perform to resolve storage display problems. Resolving SAN Performance ProblemsA number of factors can negatively affect storage performance in the ESXi SAN environment. Among these factors are excessive SCSI reservations, path thrashing, and inadequate LUN queue depth. Virtual Machines with RDMs Need to Ignore SCSI INQUIRY CacheStorage vendors might require that virtual machines with RDMs ignore SCSI INQUIRY data cached by ESXi. Software iSCSI Adapter Is Enabled When Not NeededWhen your host uses a network adapter with iBFT, the software iSCSI adapter is always enabled by default. Failure to Mount NFS DatastoresAttempts to mount NFS datastores with names in international languages result in failures. Troubleshooting Storage AdaptersIf your storage adapters experience performance problems, use the esxcli storage san commands to identify the problems. Checking Metadata Consistency with VOMAUse vSphere On-disk Metadata Analyzer (VOMA) to identify incidents of metadata corruption that affect file systems or underlying logical volumes. No Failover for Storage Path When TUR Command Is UnsuccessfulA storage path does not fail over when the TUR command repeatedly returns retry requests. Troubleshooting Flash DevicesvSphere uses flash drives for such storage features as vSAN, host swap cache, and Flash Read Cache. Troubleshooting Virtual VolumesVirtual volumes are encapsulations of virtual machine files, virtual disks, and their derivatives. Virtual volumes are stored natively inside a storage system that is connected through Ethernet or SAN. They are exported as objects by a compliant storage system and are managed entirely by hardware on the storage side. Troubleshooting VAIO FiltersvSphere APIs for I/O Filtering (VAIO) provide a framework that allows third parties to create software components called I/O filters. The filters can be installed on ESXi hosts and can offer additional data services to virtual machines by processing I/O requests that move between the guest operating system of a virtual machine and virtual disks.