Re: discard synchronous on most SSDs?

Chris Samuel
2014-03-15T04:06:33Z

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On Fri, 14 Mar 2014 06:33:24 PM Chris Samuel wrote:

> I *think* you want smartctl -i instead, and look for the field that says
> something like:
>
> ATA Version is: ATA8-ACS, ACS-2 T13/2015-D revision 3

Late night, cut and pasted the wrong line of output, mine says:

SATA Version is: SATA 3.0, 6.0 Gb/s (current: 6.0 Gb/s)

Of course that's what the drive is reporting it supports, I'm not sure whether
that's the result of what has been negotiated between the controller and drive
or purely what the drive supports.

To get more information from smartctl you can use the --identify=wb option
instead of -i and that should give you a lot more detail about what then
drives claims to (and not to) support. On the version in Kubuntu 13.10
(6.1+svn3812-1) it only reports 3 things regarding TRIM for my drives.

chris@quad:/tmp$ sudo smartctl --identify=wb -d sat /dev/sdb | egrep -i 'trim|
discard'
69 14 1 Deterministic data after trim supported
69 5 0 Trimmed LBA range(s) returning zeroed data supported
169 0 1 Trim bit in DATA SET MANAGEMENT command supported

I'm currently doing a git clone of their SVN repo to see if there's any new
functionality that will gather any more information.

cheers,
Chris
--
Chris Samuel : http://www.csamuel.org/ : Melbourne, VIC

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