Re: fdisk(8) vs gpart(8), and gnop

On 2014-06-01 11:55, Nathan Whitehorn wrote:
> On 06/01/14 08:52, Steven Hartland wrote:
>> ----- Original Message ----- From: "Mark Felder" <feld@freebsd.org>
>>
>>> On May 31, 2014, at 20:57, Freddie Cash <fjwcash@gmail.com> wrote:
>>>
>>>> There's a sysctl where you can set the minimum ashift for zfs. Then you
>>>> never need to use gnop.
>>>>
>>>> I believe it's part of 10.0?
>>>
>>> I've not seen this yet. What we need is to port the ability to set
>>> ashift at pool creation time:
>>>
>>> $ zpool create -o ashift=12 tank mirror disk1 disk2 mirror disk3 disk4
>>>
>>> I believe the Linux zfs port has this functionality now, but we still
>>> do not.
>>
>> We don't have that direct option yet but you can achieve the
>> same thing by setting: vfs.zfs.min_auto_ashift=12
>>
> Does anyone have any objections to me changing this default, right now,
> today?
> -Nathan
> 
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The only other downside to 4k sectors is that you only get a history of
32 transaction groups instead of 128. Matt Ahrens says this isn't a big
deal.

I agree with changing the default to 12, a user making a new pool with
512b disks that is that worried about performance, can always shift the
value back to 9.

I will add this to the zfs section of the handbook, and make a specific
note about this 512b issue.

The 18,000 word ZFS section of the handbook should go live within a week
or two.

-- 
Allan Jude
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