Support for WD Advanced Format disks

Olivier Smedts olivier at
Wed Aug 11 11:52:23 UTC 2010

2010/8/11, Valentin Nechayev <netch at>:
>> I'm looking into a clean, permanent solution for WD Green drives that
>> use 4096-byte physical sectors.  To summarize the information I've
>> collected so far:
> There is attempt to look from another side - is it really needed?
> Captain Obvious says that if one have a new disk, it's easy to format
> it properly - i.e. not xxx*16*63 but aligned on 4KB boundary. For
> example, set up geometry xxx*64*32 for all new disks and align GPT
> partitions on 1MB boundary. As soon as FS requests in FreeBSD are no
> less than 4KB in size, this would satisfy any disk.

That would not satisfy ZFS, which uses smaller (than 4KB) chunks for
small files. That's a big problem on RAID-Z.

> If 4KB sectors are our future for a few next years, this shall be
> implemented anyway...
> -netch-
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Olivier Smedts                                                 _
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