Knowledge Base

The VMware Knowledge Base provides support solutions, error messages and troubleshooting guides
Search the VMware Knowledge Base (KB)   View by Article ID

Repeated Extent Operation of the Same LUN to Existing VMFS volume Might Cause Data Corruption (1000319)


When an existing VMFS volume is shared across multiple hosts, an extent should be added to the VMFS volume only once, and to only one host. Repeating the same operation on more than one host might corrupt the new extent. The original base VMFS volume is unaffected.
Consider the following scenario:
Two ESX Server hosts (Host A and Host B) are managed by VirtualCenter 2.0.x. Both hosts can access a LUN (LUN X) that is formatted with VMFS-3 file format. Using VirtualCenter or a SAN management interface, present a new LUN (LUN Y) to both hosts as follows:
  1. In VirtualCenter, select Host A, right-click the VMFS-3 LUN (LUN X), and select Properties.
  2. Click the Add Extent button, add the new LUN (LUN Y) to create the extent, and then click OK.
  3. Select Host B, right-click the VMFS-3 LUN (LUN X), and select Properties.
  4. Click the Add Extent button and add LUN Y to that extent as well.
Adding the same LUN (LUN Y) as an extent to Host B corrupts the extent that was added to Host A in step 2.


Perform the following steps to create extents:
1. Present a new LUN to the ESX Server hosts and rescan all hosts to make sure that the LUN is visible to each host.
2. Add the new LUN as an extent to an existing datastore.
3. Rescan each host that is supposed to see the extent (or use a VI Client using VirtualCenter) and make sure that all hosts can now see the extended datastore.

Request a Product Feature

To request a new product feature or to provide feedback on a VMware product, please visit the Request a Product Feature page.


  • 0 Ratings

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? (4000 or fewer characters)
  • 0 Ratings