Re: Is there a "nossd" option ?

Roman Mamedov
2015-06-21T17:31:23Z

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On Sun, 21 Jun 2015 19:13:10 +0200
Swâmi Petaramesh <swami@petaramesh.org> wrote:

> Hi,
>
> Running a 3.19 Ubuntu kernel,
>
> I'm currently budling a RAID-1 BTRFS set for which every underlying device is
> a LUKS-encrypted device itself built out of a bcache device comprised of a
> mechanical HD partition + an SSD cache partition.
>
> Looks like it's working.
>
> BUT I see that BTRFS decides by itself to mount with the "ssd" option as
> bcache makes it think the device is not "rotational".
>
> However I feel that a mechanical HD plus SSD bcache should probably not be
> "SSD-optimized" as the underlying storage is indeed mechanical and bcache
> already manages the SSD part optimization by itself - and I'm afraid the "SSD
> optimization" could actually cause the mechanical storage to end up being much
> more fragmented than it should...
>
> So the question is : Is there a mount option such as "nossd" that I could use
> to inhibit the automatic SSD "choice" that BTRFS makes ?

Yes the "nossd" option (written literally like that) does in fact exist.
It would have taken you less time to try if it works, than to write this
long-winded message. :)

--
With respect,
Roman

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