Fun with IBM HGST HUH721010AL4200 9.93TB -> 10TB


Active Member
Jan 11, 2013
I bought a bunch of the drives in the title and they came with type 2 protection on them and reported 9.93TB in lsscsi/smartctl. I'm using RHEL 8.5, a SAS2308 controller, and a NetApp DS4243

I have dealt with this in the past as discussed in this thread on 8TB sun/oracle HGST drives:

These are 4Kn drives (says it right on the label), but re-sectoring them to 4096 and disabling type2 using sg_format or HUGO results in the drives continuing to report 9.93TB in smartctl/lsscsi, even after re-powering the drives. The workaround I found was to format to 512E using HUGO fastformat (presumably 512E with sg_format would work too) to get them to report full 10TB.

If anyone has an example of a retail version of this drive (e.g. not sun/netapp/ibm) and has it formatted to be 4Kn, do you have the issue with them reporting 9.93TB?

The workaround does work, but I want to open discussion to see if anyone knows why/how to properly resolve this and keep it set as 4Kn. In my case, the workaround doesn't cause a problem because ashift=12 with zfs will work fine without performance penalty.

HUGO utility in this post


Apr 18, 2011
I usually use the Report button, to report my own posts. Seems about the right level of "pinging the mods" without bothering them, I hope... ;)

It's pretty easy, then we select how long to redirect and to notify author or not...
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