4kn & 512e vSphere Support

Just a reminder for people not to create volumes with a 4K sector size with vSphere or VSAN, allot of the newer firmware revisions are now allowing 4K sector sizes for example Dell EqualLogic.

See the below screenshot as an example although the 512byte sector size is the default the adventurous or hungover IT admin amongst us may end up going with the 4K option without considering the consequences.

Screenshot 2015-09-02 10.20.28

VMware have made their support statement quite clear on this over the last few months but I thought I would repost this for the benefit of others who might not of seen this KB.

What are 4K Native and 512e drives?
Industry standard disk drives have been using a native 512 bytes sector size. However, due to the increasing demand for larger capacities, the storage industry introduced new advanced formats, which are 512-byte emulation (512e) and 4KB Native (4Kn).

4Kn is the advanced format in which the physical sectors and logical sectors are both 4,096 bytes in size.

512e is the advanced format in which the physical sector size is 4,096 bytes, but the logical sector size emulates 512 bytes sector size.

This table compares Native 512-byte sectors to the new advanced formats:

Format Logical Sector Size Physical Sector Size
512n 512 512
512e 512 4,096
4Kn 4,096 4,096

Does current GA version of vSphere and VSAN support 4K Native drives?

No. 4K Native drives are not supported in current GA releases of vSphere and VSAN.

Does current GA version of vSphere and VSAN support 512e drives?

No. 512e drives are not supported with the current versions of vSphere and VSAN due to potential performance issues when using these drives.

For further reading please see VMware KB2091600

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