Are Advanced Format/4K drives supported as RDM?

[piliran]

Hi,

I'm trying to use a 6TB HDD (WD Red/Green) which is using 4K sectors and relies on Advanced Format (512e). I've been using the HDD with ESXi on a HP proliant Gen 8 however unless I'm mapping the drive as IDE, both the AHCI or b120i (software) RAID controller don't seem to be working.

AHCI makes ESXi completely unstable while the raid controller (with RAID 0 is effectively passing the data as is) does not sees the data on the HDD properly; the system does not boot up while on bare-metal, everything works just fine.

Note that in ESXi I'm passing the HDD as an RDM - mapping the drive in SATA IDE mode (aka Legacy), seems to fix the problem... On smaller HDDs, the problem does not seem to occur. 

I've searched the forums but I can't find any relevant information on whether ESXi 5.5 or 6.0 do in fact support Advanced Format HDD (and if so if there are any restrictions) or not.

Cheers,

[a_p_ · Accepted solution]

According to VMware KB: Support statement for 512e and 4K Native drives for VMware vSphere and VSAN such drives are not supported yet for ESXi.

André

[piliran]

Thanks.

After a lot of trial, I've discovered that the hard way. I can access the HDD if I map them as SATA IDE/Legacy; mapping them as SATA AHCI makes ESXi unstable (it can't see any HDD/Storage minutes after logging in) and freezes while using the software RAID controller (B120i) does not properly read the HDD; likely the 512e puts it off.

I'm disappointed to see ESXi released in 2015 without support for a HDD standard back from 2009 :smileyalert: . If anybody has any ideas if or when AF will be supported by ESXi, please let me know.

Cheers,

[eRJe]

I was looking up more info and confirmation about this subject too when I stumbled on this post. So this means that for sure all drives >2TB will not be supported as they will have 512e formatting right? (or even 4096n)

Thanks,

Robbert

[piliran]

Basically yes.

Note that drives up to (and including) 4TB can be without AF. It depends on the specification; a quick example here from WD. However as far as I can tell, beyond 4TB all HDD come with AF (while some are 4Kn).

Further more, it looks to me that 4TB seems to be another limitation in software (just like 1TB and 2TB was some time ago in BIOS and such).

Either way, without official support it means your drive might work or might not. And if it does, there's a high chance that since AF is not properly recognized, the partitions are not properly aligned resulting in a lot of trashing. From what I can tell that's the issue I am facing when using the RAID controller - the drive is seen however incorrectly.

All in all not a situation I want to be in.

While I'm really a fan of VMw and ESXi, right now I have no choice but to go elsewhere - using the HDD in IDE mode is far from ideal. HyperV on the other hand is just as free and has had support for AF for years now. I'm completely baffled by the whole situation; to see ESXi lacking such a basic features and behind HyperV. It didn't even cross my mind that AF is not supported, not by ESXi...