ESXi hosts are unable to detect local HDDs greater than 2TB

Products

• VMware vSphere ESXi

Issue/Introduction

When ESXi hosts are attached to a RAID controller in HBA mode, you experience these symptoms:

• ESXi host is unable to detect Hard Disks greater than 2 TB
• The host has one or more SAS Hard Disks attached to RAID controller in HBA (Pass-through) mode
• The RAID controller might be able to detect the Hard Disks if configured in RAID mode

Environment

• VMware vSphere ESXi 5.5
• VMware vSphere ESXi 6.0

Cause

This issue occurs because ESXi cannot detect drives returning descriptor format sense data, especially drives greater than 2TB configured in HBA (Pass-Through) mode.

Currently, ESXi 5.5 and 6.0 does not support descriptor format for SCSI sense data.

Resolution

This issue is resolved in:

• ESXi 5.5 Patch 9. 
• ESXi 6.0 Patch 3. 

These patches allow ESXi to detect HDDs greater than 2 TB in HBA mode. Based on the current vSAN version apply an appropriate patch (Either ESXi 5.5 P09 or ESXi 6.0 P03).

 

After applying the patch:

1. Run these commands:
   
   esxcfg-advcfg -g /Scsi/SCSIEnableDescToFixedConv
   esxcfg-advcfg -s 1 /Scsi/SCSIEnableDescToFixedConv
   
   
   
2. Rescan to view all available disks.
3. Reboot an ESXi server and verify the disk availability.

Note: There are few limitations with respect to support for descriptor format sense data disk with this patch:

1. RDM (Raw Disk Mapping) is NOT supported.
2. Any application or Guest OS that uses descriptor sense data may not work as expected and is not supported.

To work around this issue, configure the RAID controller in RAID mode.

Note: RAID mode on certain controllers is unsupported for vSAN.