Advanced Format Drive ?

[Warren Block]

On Wed, 14 Nov 2012, Ronald F. Guilmette wrote:

> (And I gather from everything that has been said
> so far in this thread that if the alignment is set wrong, then the user
> is likely to pay a Big Price in terms of performance, right?)

Yes.

> ... and I am almost tempted to file a formal PR about this, i.e. the fact
> that ``guided'' partitioning doesn't allow the user to specify the alignment
> of _anything_.

There are a couple PRs like that already.

>>> Or do I need to set the alignment separately, e.g. my manually running
>>> bsdlabel?  (Normally, I've just been using what noadays is being
>>> called "guided" partitioning, you know, with the friendly curses-based
>>> GUI.  So As with fdisk, I have no real experience using bsdlabee from
>>> teh command line.  But I guess it is time that i learned how.)
>>
>> I don't know of a way to make fdisk and bsdlabel do the correct
>> alignment.
>
> That also is rather entirely perplexing to me, especially given all else
> that I have learned already from and within this conversation.

fdisk and bsdlabel are old tools.  Disks have had 512-byte blocks for a 
very long time.

> For example, I've learned that when one is using modern "Advanced
> Format) (4KB blocksize) hard disks, it is Bad (capital `B') to allow
> any partition to be aligned to anything other than (at least) a 4KB
> boundary, _and_ that newfs has already, apparently been modified/updated
> so that it's minimum default fragment size is 4KB.

The larger size was an option to newfs, the defaults have just been 
changed.

> Given these facts, I am more than a little surpised to learn (or rather
> just to realize) that the good old traditional fdisk and bsdlabel tools
> do not have ways to explicitly specify minimum alignment _and_ that
> these tools are still being distributed with FreeBSD.

There may be a way, I haven't bothered to look.  As I said, gpart does 
everything fdisk and bsdlabel can do.