From: Shaohua Li <shli@kernel.org>
To: Chris Worley <worleys@gmail.com>
Cc: linuxraid <linux-raid@vger.kernel.org>
Subject: Re: Shouldn't the /sys/block/md*/queue/max_*sectors_kb be set to the chunk size?
Date: Thu, 18 May 2017 11:50:23 -0700 [thread overview]
Message-ID: <20170518185023.3z5byy5uqpfb46w6@kernel.org> (raw)
In-Reply-To: <CANWz5fiQ1O5k43QKfurd84nwdeCZL0-EOD6p_2vp+wHaJmsVEw@mail.gmail.com>
On Thu, May 18, 2017 at 05:52:28AM -1000, Chris Worley wrote:
> I'm obviously missing something...
>
> If chunk size is a stride, why is the
> /sys/block/md*/queue/max_*sectors_kb being inherited from one of the
> underlying devices rather than being set to the chunk size or the
> drive multiple of their max sector settings?
We set it to chunk size unless underlying disks have a smaller max_*sectors_kb.
Underlying disks usually have much bigger max_sectors than chunk size.
> Or, in other words, would the chunk size setting have a natural upper
> bound/limit of one of the drives max_sectors, or the sum of all of the
> constituent drives max sectors?
I don't know such upper bound and don't think it matters. The max_sectors
basically is the size we split the bio to fit for one underlying disk.
Thanks,
Shaohua
next prev parent reply other threads:[~2017-05-18 18:50 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-18 15:52 Shouldn't the /sys/block/md*/queue/max_*sectors_kb be set to the chunk size? Chris Worley
2017-05-18 18:50 ` Shaohua Li [this message]
2017-05-18 21:33 ` Chris Worley
2017-05-18 21:48 ` Shaohua Li
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