svn commit: r304142 - head/usr.sbin/bsdinstall/partedit

[Nathan Whitehorn]

On 08/18/16 21:15, Warner Losh wrote:
> On Thu, Aug 18, 2016 at 6:56 AM, Allan Jude <allanjude at freebsd.org> wrote:
>> On 08/18/16 05:50 AM, Dag-Erling Smørgrav wrote:
>>> Nathan Whitehorn <nwhitehorn at freebsd.org> writes:
>>>> OK. In which configurations? My Dell servers, for instance, don't do
>>>> this. How are they set up? What drivers are being used? Is this
>>>> something that affects passthrough disks, RAIDs, disk images?
>>> Most LSI MegaRAID controllers don't have real passthrough, only JBOD.
>>> You can query the drive with "camcontrol identify passX", but the
>>> controller does not report a stripe size for the volume (mfidY).
>>>
>>>> The point is that *if the reported stripe size is wrong*, more things
>>>> than partition alignment in the installer will suffer for it.
>>> It's not wrong, it's non-existent, and I'm getting really tired of
>>> repeating myself.
>>>
>>>> Fixing the installer with a bandaid in the run-up to a release is
>>>> fine, but *we need to fix the underlying problem*.
>>> We can't, because hardware sucks, and I'm getting really tired of
>>> repeating myself.
>>>
>>> DES
>>>
>> Which makes more sense:
>>
>> A) If stripesize == 0, use some sane value like 4096
> I don't like this.
>
>> B) Some other combination that uses the reported stripe size, unless it
>> is 0, in which case it uses 4096 (or some other value controlled by a
>> different new sysctl)
> Don't like this so much.
>
>> C) create kern.geom.min_stripe_size with a default of 512, but users can
>> set 4096 if they use only 4k devices. (doesn't really solve the problem
>> for the installer)
> Default it to 4k, and allow users to set it to 512. If the drive
> reports < this value
> report this value instead. You'll need to make this a tunable. Then the upper
> layers wouldn't care. There's a small chance that some SD cards might be
> reporting values that are too large. But I think it is confined to SD cards and
> if I see too many more I'll do something specific in the SD driver.
>
> Warner
>
>

That sounds good to me and I think can clean up a lot of code and 
potential foot-shooting. Who is planning to make the patch? I'm happy to 
do anything that would be helpful.
-Nathan