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New LUN Not Detected After Rescan

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You present new LUN(s) to the ESXi Host / Cluster from the Pure Storage FlashArray. Upon initiating a rescan you verify that the expected LUN(s) are not seen on the ESXi Host as available devices under the "Storage Adapters" section. While investigating the issue you are able to confirm other LUNs are successfully mapped to the ESXi Host without issue.

Note: If checking from the command line of the ESXi Host the LUN(s) would be missing the following command:

'esxcli storage core device list'


Upon reviewing the ESXi Host 'vmkernel' logs you are able to locate the following error message being reported at the time of rescan:

2016-04-23 22:21:43.483Z cpu13:34281087)WARNING: ScsiPath: 903: The number of paths allocated has reached the maximum: 1024. Path: vmhba2:C0:T14:L0 will not be allocated. This warning won't be repeated until some paths are removed.

Additionally, when running the following command from the ESXi Host command line interface it reports a value of '1024':

grep vmhba esxcfg-mpath -b |wc -l


The error message above indicates that the the maximum number of total paths allowed to an ESXi Host has been reached. You will not be allowed to add additional LUN(s) to the ESXi Host until this is addressed.

This can be resolved the following ways:

  • Reduce the number of paths to each LUN so they can add the additional LUN(s) as needed.
  • Reduce the number of total LUNs (if possible) to the ESXi Host so they can have desired number of paths.
  • Map the LUNs to a new ESXi Host / Cluster.

This decision needs to be made by the customer to determine what the best scenario for their environment is. We do not have control over this variable within the ESXi Host. If they have additional directions kindly direct them to VMware Support as needed.

Review the following VMware links below for additional information: