From: Neil Brown <neilb@suse.de>
To: Michael Evans <mjevans1983@gmail.com>
Cc: Doug Ledford <dledford@redhat.com>,
Bill Davidsen <davidsen@tmr.com>,
Joe Bryant <tenminjoe@yahoo.com>,
linux-raid@vger.kernel.org
Subject: Re: Spare drive won't spin down
Date: Tue, 18 May 2010 10:50:49 +1000 [thread overview]
Message-ID: <20100518105049.490aa652@notabene.brown> (raw)
In-Reply-To: <AANLkTiknwELDEgA2LKbhOkNJWlm-wxBozMZ4i0BUFtu2@mail.gmail.com>
On Mon, 17 May 2010 17:38:04 -0700
Michael Evans <mjevans1983@gmail.com> wrote:
> You should make it a sysfs controllable option to keep the counter
> updated on spare discs or not. The default can be to keep it within
> one as you currently are patching it to. Then later you can change
> the default to the higher performance setting. Better, the presence
> of that file can be used to test if the kernel supports it, and if it
> doesn't initramfs scripts can react accordingly.
There really isn't any need for user-space to know - this is an entirely
in-kernel thing. mdadm already supports assembling arrays with widely
different event_counts. It just gives them to the kernel and lets it make
the final decision.
And I think it is stretching things to call this a performance setting. It
only changes behaviour when add devices is added/removed/failed or when an
array is started or reshaped. None of those happen often enough that an
extra spin-up is really going to be an issue.
It is more an issue of simplicity and elegance. I don't think a sysfs option
is appropriate for that.
But thanks for the suggestion.
NeilBrown
next prev parent reply other threads:[~2010-05-18 0:50 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-06 17:49 Spare drive won't spin down Joe Bryant
2010-05-07 5:07 ` Michael Evans
2010-05-07 7:39 ` Joe Bryant
2010-05-07 6:20 ` Neil Brown
2010-05-07 7:40 ` Joe Bryant
2010-05-07 9:47 ` Neil Brown
2010-05-07 10:05 ` Joe Bryant
2010-05-10 16:59 ` Bill Davidsen
2010-05-11 20:53 ` Neil Brown
2010-05-17 18:11 ` Doug Ledford
2010-05-18 0:23 ` Neil Brown
2010-05-18 0:38 ` Michael Evans
2010-05-18 0:50 ` Neil Brown [this message]
2010-05-18 0:20 ` Neil Brown
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