Support > Knowledge Base

Knowledge Base

Search the Knowledge Base:

Guided Search

Products:

Search In:

Persistent Binding Issue with Raw Device Mapping

Details

Are there any additional instructions to the SAN Configuration Guide regarding setting up SAN arrays for clustering when using persistent binding and raw device mapping?

Solution

No additional action is required if the virtual machines use raw device mappings (RDMs), and all the LUNs referenced by the RDMs are still accessible by ESX Server using the original LUN numbers. ESX Server will access the LUNs over whatever paths are currently available when the server is booted.

However, you need to edit the virtual machine configuration files (.vmx) if the virtual machines directly access raw devices and both of the following are true:

All the LUNs referenced by the virtual machines are still accessible by ESX Server.
A new cable installation or removal changed the original paths.

For example, assume a LUN originally has four paths:

      vmhba3:3:5
      vmhba3:4:5
      vmhba4:3:5
      vmhba4:4:5

If a virtual machine configuration file contains lines such as:

     scsi0:0.present = "TRUE"
     scsi0:0.name = "vmhba3:3:5:0"

and ESX Server has been rebooted after a pulled cable caused the path vmhba3:3:5 to be removed, then you need to locate the new canonical name for the LUN. If all paths from vmhba3 are no longer accessible, and assuming that target numbers have not changed, then the canonical name will be vmhba4:3:5. In this example, you must edit the virtual machine configuration file and change the scsi0:0.name value as follows:

     scsi0:0.present = "TRUE"
     scsi0:0.name = "vmhba4:3:5:0"

If pulled cables, added LUNs and deleted LUNs have caused the SCSI target numbers to change, you need to determine the new vmhba and target number for the LUN and edit the virtual machine configuration file accordingly.

If the virtual machines directly access raw devices or RDMs, and the LUNs referenced by those raw devices or RDMs are no longer accessible by ESX Server, then the virtual machines will not start until you edit the virtual machine configuration file and remove the references to those raw devices or RDMs.

For more information about resetting persistent bindings, see the SAN Configuration Guide at www.vmware.com/pdf/esx25_san_cfg.pdf.

For more information about raw device mapping, see www.vmware.com/pdf/esx25_rawdevicemapping.pdf.

Keywords

1824; urlz; esx252; cable; pull

Feedback

Actions

KB Article: 1824
Updated: Aug 14, 2009

Products:
VMware ESX
Product Versions:
VMware ESX 2.5.x

Did this article help you?
This article resolved my issue. This article did not resolve my issue. This article helped but additional information was required to resolve my issue.
What can we do to improve this information? (2000 or fewer characters)