From: Alan McKinnon <alan.mckinnon@gmail.com>
To: gentoo-user@lists.gentoo.org
Subject: Re: [gentoo-user] SSDs, ext4, fstrim, discard ...
Date: Wed, 12 Oct 2011 01:17:02 +0200 [thread overview]
Message-ID: <20111012011702.73eef020@rohan.example.com> (raw)
In-Reply-To: <4E94C2F3.6000607@xunil.at>
On Wed, 12 Oct 2011 00:28:03 +0200
"Stefan G. Weichinger" <lists@xunil.at> wrote:
> Am 12.10.2011 00:05, schrieb Alan McKinnon:
>
> > Yes, you misunderstand how fstrim works. It's not up to you to say
> > what it does exactly, it's up to the drive firmware and possibly
> > the kernel. It's actually fully described in the man page right
> > there in the part for option -v :-)
>
> So it only tells me "something"?
No, it's giving you a fact (and slightly misrepresenting it in the
output).
You asked the drive firmware for a favour - to please check if anything
can be discarded and if so to discard it.
<cue Mafia voice a la GodFather>
The firmware checked that it *could* discard X bytes and then figured
well, maybe it will, maybe it won't, maybe it'll do it on it's own
good time, but what the heck - tell the user anyway how many bytes X
is. Maybe that'll make the user happy so he'll stfu and go away......
The command leads you to believe the discard was actually done, but
that's not necessarily true :-)
It's probably a case of the drive knows much better than you what it
should do.
--
Alan McKinnnon
alan.mckinnon@gmail.com
next prev parent reply other threads:[~2011-10-11 23:19 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-11 20:56 [gentoo-user] SSDs, ext4, fstrim, discard Stefan G. Weichinger
2011-10-11 22:05 ` Alan McKinnon
2011-10-11 22:28 ` Stefan G. Weichinger
2011-10-11 23:17 ` Alan McKinnon [this message]
2011-10-12 7:59 ` Stefan G. Weichinger
2011-10-11 22:05 ` Neil Bothwick
2011-10-11 22:26 ` Stefan G. Weichinger
2011-10-13 21:12 ` Stefan G. Weichinger
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