[OpenIndiana-discuss] HDD Upgrade problem

[Richard Elling]

On Jun 11, 2012, at 9:58 PM, Rich wrote:

> On Tue, Jun 12, 2012 at 12:50 AM, Richard Elling
> <richard.elling at richardelling.com> wrote:
>> On Jun 11, 2012, at 6:08 PM, Bob Friesenhahn wrote:
>> 
>>> On Mon, 11 Jun 2012, Jim Klimov wrote:
>>>> ashift=12 (2^12 = 4096). For disks which do not lie, it
>>>> works properly out of the box. The patched zpool binary
>>>> forced ashift=12 at the user's discretion.
>>> 
>>> It seems like new pools should provide the option to be created with ashift=12 even if none of the original disks need it.  The reason is to allow adding 4K sector disks later.
>> 
>> I don't disagree, in principle. However, history has shown that people don't plan very well
>> (eg, reason #1 dedup exists). Is there some other way to be more clever?
>>  -- richard
> 
> I believe that the consensus the last time this came up was agreement
> on that point, but contention over how the semantics of specifying it
> should work?

For illumos, this is solved by overriding the physical block size parameter
in the sd.conf file.

The answer to "will it work" depends on the logical block size reported by the drive.

The answer to "will it work with best efficiency" depends on the physical block
size reported by the drive. No surprises here.
 -- richard

-- 

ZFS storage and performance consulting at http://www.RichardElling.com