svn: head/usr.bin: . trim

[Steven Hartland]

On 30/11/2018 22:09, Eugene Grosbein wrote:
> 01.12.2018 4:29, Steven Hartland wrote:
>
>> On 30/11/2018 21:16, Eugene Grosbein wrote:
>>> 30.11.2018 21:23, Warner Losh wrote:
>>>
>>>> So I'm back to my point: we should just put it into dd and move on with our lives. It's really the right place for it.
>>> Why can't we have two implementations? Diversity is good thing.
>>>
>>> I can imagine erasing a partition with ZFS Cache or ZIL inside and
>>> "trim /dev/da0p2 /dev/da0p3" looks much better :-)
>> ZFS already does that no need for a separate tool
> Think of media taken out of (possibly already dead) ZFS-based to UFS-only system.
>
> By the way, how exactly do you trim previously ZIL partition withing working ZFS-based system?
>
You could use camcontrol which can perform a secure erase on the device, 
but that's obviously device wide not a specific partition.

What I was referring to is ZFS performs a delete of blocks when it 
initializes a volume, so there's usually no need to perform a manual 
step there.

For reference this behavior can be disabled by setting 
vfs.zfs.vdev.trim_on_init=0

     Regards
     Steve