Is TRIM working with gmirror?

[Miroslav Lachman]

Steven Hartland wrote:
> ----- Original Message ----- From: "Steven Hartland"
> <killing at multiplay.co.uk>
>
>> ----- Original Message ----- From: "Miroslav Lachman" <000.fbsd at quip.cz>
>>
>>> Steven Hartland wrote:
>>> [...]
>>>> Unless you have a specific reason for using gmirror I would strongly
>>>> advise trying ZFS instead, it will definitely support TRIM in that
>>>> config and comes with a host of other benefits too :)
>>>
>>> The specific reason is performance and memory consumption. We need
>>> every piece of performance and all memory to MySQL daemon, so this is
>>> why gmirror was choosen.
>>> We have ZFS on other purposes machines for years (from 7.x days), so
>>> I can say "I have a lot of experiences" (good and bad too).
>>> In some tests, ZFS is about 50% slower than UFS.
>>>
>>> What about graid(8) mirror instead of gmirror(8)? Is there better
>>> support for TRIM on UFS?
>>
>> Actually looking at it gmirror should support delete no problem see
>> g_mirror_init_disk GEOM::candelete.
>>
>> So you might want to add some debugging around there to see whats
>> happening.
>
> Double checked this on HEAD and it definitely works as expected.

I am not able to understand C sources, so I cannot check it myself. But 
if it is supported, why I see the warning message at boot?

Miroslav Lachman