On Wed, 21 Mar 2012, Holger Kiehl wrote:

On Tue, 20 Mar 2012, Hugh Dickins wrote:

quoted

It appears to be a bug in the Vertex 2: I did receive one other such
report on a Vertex 2 fourteen months ago, and in the absence of further
reports, we decided to consider that user's drive defective.  I wonder
if Holger's drive is defective, or if it's true of all Vertex 2s, or
if it depends on the firmware revision, and a later revision fixes it.

I have three of those drives put together via MD to a raid 0 and I do
not think they are defective, since they worked (without discard) so far.
Firmware is also the new-es it's 1.35, just checked with OCZ website.

Thanks very much for checking and reporting back.

Thank you for the pointer with the firmware, I have posted a support
question at OCZ.

Great: please let me know if they have anything of interest to add.

I've now ordered a Vertex2 myself, to see if it sheds any light on
what goes on.  Probably not; but my Vertex1 has recently started giving
errors, so I might as well use a 2 to replace it.  By the time I came
to investigate last year's report, the Vertex3 was imminent, so I
held on for that; but it turned out not to share the problem.

quoted

But if there's no good firmware for the Vertex 2, I'm not so sure
what to do: two reports in fourteen months, on a superseded drive -
is that strong enough to disable a feature which appeared to offer
some advantage on others?

No, I agree that one should not disable a feature that is useful to so
many, for the reasons you mention. However, it would be good if there
is some way to disable this, other then having to always patch the kernel.

I should not exaggerate the effectiveness of the swapon at discard, on
any drive I tried: "useful to so many" is probably going too far.  I've
called the effect "slight": when I've time I shall measure again just
what that amounts to, and whether it's worth the effort of doing anything
cleverer than Shaohua's patch - quite possibly not.

Hugh

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