VMware Raw device mapping disc accessibility issue
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VMware Raw device mapping disc accessibility issue


Article ID: 324320


Updated On:


VMware vSphere ESXi


  • Issue accessing some RDM devices depending on standby path.
  • Inability to read/write RDM discs although they are visible (failing dd if=/dev/sdx of=/tmp/some count=1)


VMware vSphere ESXi 6.5
VMware vSphere ESXi 6.0
VMware vSphere ESXi 5.5
VMware vSphere ESXi 6.7


This behavior might be caused by cached SCSI INQUIRY data that interferes with specific guest operating systems and applications.

When the ESXi host first connects to a target storage device on a SAN, it issues the SCSI INQUIRY command to obtain basic identification data from the device. By default, ESXi caches the received SCSI INQUIRY data (Standard, page 80, and page 83) and the data remains unchanged afterward.


To resolve this issue, Configure the virtual machine with RDM to ignore the SCSI INQUIRY cache.
  1. Login to ESXi shell
  2. In .vmx configuration file.
  3. Add the parameter:
scsix:y.ignoreDeviceInquiryCache = "true"