RAIDframe and alignment on 4K-sector disks?

["John D. Baker" <jdbaker%mylinuxisp.com@localhost>]

I'm sure this has been discussed at length before.  I recall reading a
thread (perhaps one I started) some time ago.

I'm about to have my first adventure with disks with 4K sectors.  The plan
is to make a RAID-5 across 3 2TB disks.

As such, I can still use 'disklabel' to prepare the component disks and
then use 'gpt' to partition the RAID itself.

Given the above, SecPerStripeUnit should be a multiple of 16--2 data disks
with 8 emulated 512-byte sectors per 4K physical sector per disk, yes?

Does RAIDframe guarantee that what it reports as "sector 0" is aligned to
the stripe size?  Once that's known or accounted for, it's a simple matter
to make 'gpt' respect the stripe-size alignment.

As long as the RAID and the partitioning are aligned to the stripe size,
it's a simple matter to give 'newfs' the approrpriat arguments to "-b"
and "-f" to make sure blocks/fragments are as well.

Anything else I should be considering?

Perhaps something on RAIDframe, 4K-sector disks and filesystem alignment
should be in the "Disks and File Systems" section of:

  http://netbsd.org/docs/#documentation-howtos

?

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