From: Greg Banks <gnb@sgi.com>
To: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: David Rees <drees76@gmail.com>, linux-nfs@vger.kernel.org
Subject: Re: Horrible NFS Client Performance During Heavy Server IO
Date: Tue, 17 Mar 2009 15:43:59 +1100 [thread overview]
Message-ID: <49BF2A8F.7030607@sgi.com> (raw)
In-Reply-To: <1236978608.7265.41.camel-rJ7iovZKK19ZJLDQqaL3InhyD016LWXt@public.gmane.org>
Trond Myklebust wrote:
> On Fri, 2009-03-13 at 13:36 -0700, David Rees wrote:
>
>>
>
> You don't need conv=fdatasync when writing to NFS. The close-to-open
> cache consistency automatically guarantees fdatasync on close().
>
Yes...but at least some versions of dd will print a performance number
at the end, where the time delta used in the calculation includes the
fdatasync() time but not the close() time. So conv=fdatasync is a
useful trick to get accurate performance numbers from dd. Personally I
don't use that metric from dd because it's a simple overall average and
I like to watch the time behaviour of the transfer rate.
--
Greg Banks, P.Engineer, SGI Australian Software Group.
the brightly coloured sporks of revolution.
I don't speak for SGI.
prev parent reply other threads:[~2009-03-17 4:39 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-13 20:36 Horrible NFS Client Performance During Heavy Server IO David Rees
2009-03-13 21:10 ` Trond Myklebust
2009-03-13 21:32 ` David Rees
2009-03-13 21:40 ` Trond Myklebust
2009-03-13 21:59 ` David Rees
2009-03-13 22:29 ` Trond Myklebust
2009-03-13 23:05 ` David Rees
2009-03-17 4:54 ` Greg Banks
2009-03-17 6:28 ` David Rees
[not found] ` <1236978608.7265.41.camel-rJ7iovZKK19ZJLDQqaL3InhyD016LWXt@public.gmane.org>
2009-03-17 4:43 ` Greg Banks [this message]
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