Re: Samsung SSD TRIM [Was: Heads up]

From: Warner Losh <imp_at_bsdimp.com>
Date: Fri, 15 Apr 2016 07:22:51 -0600
> On Apr 15, 2016, at 7:14 AM, Tommi Pernila <tommi.pernila_at_iki.fi> wrote:
> 
> Hi,
> 
> On Friday, 15 April 2016, Steven Hartland <killing_at_multiplay.co.uk> wrote:
> 
>> On 15/04/2016 09:11, Kurt Jaeger wrote:
>> 
>>> Hi!
>>> 
>>> avg wrote:
>>> 
>>>> For what it's worth, I have been using the following SSDs since
>>>> September of 2015 :
>>>> 
>>>> ada2: <Samsung SSD 850 EVO 120GB EMT01B6Q> ACS-2 ATA SATA 3.x device
>>>> ada3: <Samsung SSD 850 EVO 120GB EMT01B6Q> ACS-2 ATA SATA 3.x device
>>>> 
>>> I have one in use with zfs and trim:
>>> 
>>> ada1: <Samsung SSD 840 EVO 250GB EXT0BB6Q> ACS-2 ATA SATA 3.x device
>>> 
>>> Works as my ports build hosts, and is fine as far as I can see.
>>> 
>>> Prior to Warners commit there was no NCQ TRIM support in FreeBSD, so
>> while it was working with standard non-NCQ TRIM (and I can corroborate that
>> as we use the 840's and 850's all over with ZFS with TRIM enabled) its
>> possible that it could cause issues when NCQ TRIM comes into play.
>> 
>> From what I read when this issue first came to light, I believe the actual
>> issue was a Linux kernel bug not a FW bug in Samsung drives that caused the
>> corruption. This is the thread which details said issue:
>> http://www.spinics.net/lists/raid/msg49440.html
>> 
>> 
> Here is a link to the commit that fixed the Linux kernel bug.
> https://git.
> kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=f3f5da624e0a891c34d8cd513c57f1d9b0c7dadc
> 
> Mounting a Samsung SSD with a linux kernel with trim enabled without this
> commit can cause issues.

Right, that bug allocates space for the TRIM message to be queued. FreeBSD
already does that, so that’s not going to be an issue. This was the issue I referred
to in a prior message.

Both the Samsung 840 and 850 are black listed as far as NCQ trim are concerned.
I’ve had other people that have tested them w/o my blacklisted entries, and there
are issues at least with the 840 that are firmware related.

Warner

Received on Fri Apr 15 2016 - 11:22:55 UTC

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