[OpenIndiana-discuss] Hitachi 4 TB disks + HP Microserver + OI 151 + ZFS

[Mark]

There are two issues.

The first is correct partition alignment, the second ashift value.

In "theory", I haven't tested this yet, manually creating the slices 
with a start position to sector 64 and using slices instead of whole 
disks for the zpool devices, and creating with an ashift of 12 may 
produce the desired outcome.

I have used 4k disks (wd20ears) in 3 and 4 disk raidz pools, but they 
are used for archiving, so just have data dumped to them.
Few issues on Sata ports, but dodgy on SAS.


Mark

On 1/05/2012 8:23 a.m., Peter Wood wrote:
> I'm building a storage server with Dell MD1000 DAS and I just bought 30
> drives with 4K sectors.
>
> One of the reasons I selected the "new" 4K sector is so I can easily find
> replacement drives 2-3 years from now when they start failing. Looks like
> this was a huge mistake.
>
> I'm fine if the drives report 512B sectors and work in slower legacy mode
> as long as they work reliable but seems that this may not be the case. On
> top of that my internal drives that make the rpool have 512B sectors so I'm
> not sure how workarounds will effect this pool.
>
> Is it fair to say that if one uses 4K drives he will run into alignment
> issue sooner or later?
>
> I'm really puzzled what to do here.
>
> Should I try to replace the drives with 512B ones before the storage goes
> life?
>
> Any thoughts?
>
> Thank you
> Peter
>
> On Mon, Apr 30, 2012 at 7:54 AM, Richard Elling<
> richard.elling at richardelling.com>  wrote:
>
>> On Apr 29, 2012, at 7:38 PM, Gordon Ross wrote:
>>
>>> On Sun, Apr 29, 2012 at 8:46 PM, Richard Elling
>>> <richard.elling at richardelling.com>  wrote:
>>>>
>>>> On Apr 29, 2012, at 11:45 AM, George Wilson wrote:
>>> [...]
>>>>>
>>>>> Speaking of 4K sectors, I've taken a slightly different approach that
>> fixes this outside of ZFS. The idea is to allow sd to override the
>> physical-block-size which ZFS will pick up. The way this works is you can
>> specify the Vendor/Product id in sd.conf. Here's an example:
>>>>>
>>>>> sd-config-list = "NETAPP  LUN, "physical-block-size:4096";
>>>>
>>>> This is the preferred solution and there are several implementations
>> running
>>>> around in various stages of test/release/acceptance. I look forward to
>> getting this
>>>> upstream :-)
>>>>   -- richard
>>>
>>> Providing a work-around in "sd" is great.  We should do that, at least.
>>>
>>> But is it sufficient?  What happens if I replace a mirrored drive with
>>> 512 byte sectors with one having 4k sectors?  What if I want to plan
>>> ahead for that?  Maybe in only some of my ZFS pools but not all?
>>> It would seem that a pool-level override for "ashift" might also be
>> useful.
>>
>> ashift is set for the top-level vdev at creation time. So you have to
>> override
>> prior to creation of the mirror.
>>   -- richard
>>
>> --
>> ZFS Performance and Training
>> Richard.Elling at RichardElling.com
>> +1-760-896-4422
>>
>>
>>
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