From: Sage Meng <lkkey80@gmail.com>
To: Jeff Layton <jlayton@kernel.org>
Cc: ceph-devel@vger.kernel.org
Subject: Re: Is there a way to make Cephfs kernel client to send data to Ceph cluster smoothly with buffer io
Date: Fri, 13 Nov 2020 10:08:42 +0800 [thread overview]
Message-ID: <CAF8vKShk8h2xz_+5qwZ=VkPGtnFkfw_u-5+6LP-_88=ahpKb2Q@mail.gmail.com> (raw)
In-Reply-To: <cf0b22ada6eea3a23b84a945208066aeadd822b3.camel@kernel.org>
It would be nice if there was a mount option to have such parameters
adjusted that only influence CephFS Kernel Client.
Jeff Layton <jlayton@kernel.org> 于2020年11月12日周四 下午11:59写道：
>
> On Thu, 2020-11-12 at 23:17 +0800, Sage Meng wrote:
> > Hi All,
> >
> > Cephfs kernel client is influenced by kernel page cache when we
> > write data to it, outgoing data will be huge when os starts to flush
> > page cache. So Is there a way to make Cephfs kernel client to send
> > data to ceph cluster smoothly when buffer io is used ? Better a way
> > that only influence Ceph IO not the whole system IO.
>
> Not really.
>
> The ceph client just does what the VM subsys asks it to do. If the VM
> says "write out these pages", then it'll do it -- otherwise they'll just
> sit there dirty.
>
> Usually you need to tune things like the dirty_ratio and
> dirty_background_ratio to smooth this sort of thing out, but those are
> system-wide knobs.
>
> Another alternative is to strategically fsync or syncfs from time to
> time, but that's sort of outside the scope of the kernel client.
> --
> Jeff Layton <jlayton@kernel.org>
>
prev parent reply other threads:[~2020-11-13 2:08 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-12 15:17 Is there a way to make Cephfs kernel client to send data to Ceph cluster smoothly with buffer io Sage Meng
2020-11-12 15:59 ` Jeff Layton
2020-11-13 2:08 ` Sage Meng [this message]
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