The Physical block size reported by the device is not supported

Since my ESXi hosts are upgraded to VMware vSphere ESXi 6.5, the vmkernel.log is constantly spammed with warnings reporting that the physical block size from my LUNs, provided by a FreeNAS storage, have an unsupported block size.

WARNING: ScsiPath: 4394: The Physical block size "131072" reported by the path vmhba64:C0:T4:L0 is not supported. The only supported physical blocksizes are 512 and 4096
WARNING: ScsiDeviceIO: 6462: The Physical block size "131072" reported by the device naa.6589cfc0000000572b71f35019e9c31f is not supported. The only supported physical blocksizes are 512 and 4096

I'm using FreeNAS-9.10.2 with iSCSI LUNs backed by a ZFS volume. The physical blocksize is reported as the ZFS recordsize which is 128K by default.

[root@freenas01] ~# zfs get recordsize flash
NAME   PROPERTY    VALUE   SOURCE
flash  recordsize  128K    default

To get rid of the warnings, activate "Disable Physical Block Size Reporting" in the iSCSI Extent configuration.

Sharing > Block (iSCSI) > Extents > Edit > Disable Physical Block Size Reporting

Leave a Comment

NOTE - You can use these HTML tags and attributes:
<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>