Re: TRIM support in drivers and dm/md?

[Jeff Layton <laytonjb@att.net>]

>>>> Do many of the SATA controllers support TRIM? (i.e. pass
>>>> the TRIM command to the SSD). Does anyone know
>>>> anything about dm/md supporting TRIM? (I'm thinking LVM
>>>> and software RAID tools).
>
>>> As far as I know, there's nothing to be done in any SATA controller
>>> driver to support TRIM. It's just up to the drive whether it 
>>> understands
>>> the command.
>
>> That's the rub. I've heard that many drivers don't understand
>> the command. So I'm curious what drivers do and any experience
>> anyone might have.
>
> Note the distinction between "drive" and "driver"...  I agree with 
> what Matthew says.
>

Oops - sorry I missed "drive" vs. "driver".

I've heard from other places that drivers need to pass along
the TRIM command to the drives but that many drivers don't
do this. I assume that the best way to determine if this is
accurate is to test the controller drivers or ping the maintainers.

Thanks!