From: jvogt <jvogt@adon.li>
To: Ming Lei <tom.leiming@gmail.com>,
Matthew Eaton <m.eaton82@gmail.com>,
fio@vger.kernel.org, Carl Zwanzig <cpz@coraid.com>
Subject: Re: correct file size to use
Date: Mon, 17 Mar 2014 21:13:47 +0100 [thread overview]
Message-ID: <5327577B.8050703@adon.li> (raw)
In-Reply-To: <CACVXFVN9O7HF6LJ=k-mygGHLWcpsQ3chWkkukdp+rFqnunJ60w@mail.gmail.com>
Am 17.03.2014 03:55, schrieb Ming Lei:
> On Mon, Mar 17, 2014 at 7:16 AM, Matthew Eaton
>> Tested on my system and saw no difference in performance. Direct io
>> will bypass the page cache so the only thing that comes to mind would
> Looks I miss the '--direct=1' parameter, :-(
>
>> be an on-device cache, though, I would think the difference in
>> performance would be more dramatic if that were the case.
> Another possible cause might be related with storage for the
> big file. If the file is stored in lot of fragments of the disk, accessing
> the whole file might become slower than just the first 10M, but not
> sure if there is so big difference(30%).
> Direct io
will bypass the page cache so the only thing that comes to mind would
be an on-device cache, though, I would think the difference in
performance would be more dramatic if that were the case.
This could be possible - I'm not so sure how to check that...
My setup is the following:
RHEL6.5 as virtual machine via VMWare - the storage is a Dell Equallogic
Storage connected via ISCSI to the host. These tests are not made via NFS.
I just wanted to make some tests before taking it all in production.
Thank you all for your answers!
Josef
next prev parent reply other threads:[~2014-03-17 20:14 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-15 11:10 correct file size to use jvogt
2014-03-16 12:12 ` Ming Lei
2014-03-16 23:16 ` Matthew Eaton
2014-03-17 2:02 ` Carl Zwanzig
2014-03-17 2:55 ` Ming Lei
2014-03-17 20:13 ` jvogt [this message]
2014-03-17 20:34 ` Sitsofe Wheeler
2014-03-17 20:40 ` jvogt
2014-03-18 0:54 ` Carl Zwanzig
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5327577B.8050703@adon.li \
--to=jvogt@adon.li \
--cc=cpz@coraid.com \
--cc=fio@vger.kernel.org \
--cc=m.eaton82@gmail.com \
--cc=tom.leiming@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.