Dangerously dedicated mode with FreeBSD 10.1

[Warren Block]

On Fri, 21 Nov 2014, Nathan Whitehorn wrote:

>
> On 11/21/14 07:26, Warren Block wrote:
>> On Fri, 21 Nov 2014, Rostislav Krasny wrote:
>> 
>>> Hi,
>>> 
>>> I've a server with FreeBSD 7.4-STABLE that uses two phisical disks in
>>> a so called "dangerously dedicated mode". There is no other operating
>>> system and no plan to install anything else but FreeBSD. So in my case
>>> this is not dangerous mode at all.
>>> 
>>> I want to upgrade it by installing FreeBSD 10.1 from scratch and I
>>> want to use the dedicated disk mode again. How could I do that?
>>> 
>>> If I understand it right the new bsdinstall(8) doesn't support the
>>> dedicated disk mode, the old sysinstall(8) is already dead and the
>>> only solution is a manual disk partitioning from shell. The 2.6.5.
>>> Shell Mode Partitioning section of the Handbook is very terse about
>>> that.
>> 
>> If you are determined, it should be possible to select a bsdlabel-only 
>> format with the Manual partitioning option in the menus, or enter Shell 
>> mode on startup and create it with gpart or even bsdlabel.  That said, I 
>> can't think of any advantages of using a bare bsdlable at all.  With 10.1, 
>> GPT is available, supports large disks, and is easily alignable.*
>
> Right, just select "BSD" as the partition type.
>
>> *: although it is reported that bsdinstall for 10.1 does not automatically 
>> do 4K alignment.  But at least there are advantages to using it as a 
>> partition scheme.
>
> This has never been true. It does 4K alignment on disks with 4K physical 
> sectors (no matter what the logical sector size is). If you have disks with 
> larger sectors or preferred boundaries (e.g. a striped RAID), it will also 
> align to that.

I know that it did not automatically do that alignment originally, which 
was why I entered PR 161720:
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=161720

After that, I thought it was fixed, and now this appears to be a 
regression:
http://forums.freebsd.org/threads/does-bsdinstall-in-10-1-properly-partition-ssds.48993/