[OpenIndiana-discuss] HDD Upgrade problem

[George Wilson]

On Jun 12, 2012, at 12:58 AM, 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?
> 
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Illumos has a way to override the physical block size of a given disk by using the sd.conf file. Here's an example:

sd-config-list =
	"DGC     RAID", "physical-block-size:4096",
	"NETAPP  LUN", "physical-block-size:4096";


By adding the VID PID values into the sd-config-list along with the 'physical-block-size' parameter you can override the value that the disk will use for it's block size. ZFS will pick this up and use the correct ashift value.

- George