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From: Bernd Schubert <bschubert@ddn.com>
To: Mark Seger <mjseger@gmail.com>
Cc: Laurence Oberman <loberman@redhat.com>, Linux fs XFS <xfs@oss.sgi.com>
Subject: Re: xfs and swift
Date: Mon, 25 Jan 2016 19:33:13 +0000	[thread overview]
Message-ID: <56A67878.3080803@ddn.com> (raw)
In-Reply-To: <CAC2B=ZEJ7cSnpzpfRBfwfEnZUsLBQe=YW2fuvbVF75OjmYmOOw@mail.gmail.com>

Hi Mark!

On 01/25/2016 08:00 PM, Mark Seger wrote:
> hey bernd, long time no chat.  it turns out you don't have to know what
> swift is because I've been able to demonstrate this behavior with a very
> simple python script that simply creates files in a 3-tier hierarchy.  the
> third level directories each contain a single file which for my testing are
> all 1K.

So what is the script exactly doing? Does it create those files
sequentially per dir or randomly between those dirs?

Btw, I had been talking about that issue at linux plumbers in 2013

https://www.youtube.com/watch?v=N_bZOGZAb-Y

> 
> I have played wiht cache_pressure and it doesn't seem to make a difference,
> though that was awhlle ago and perhaps it is worth revisiting. one thing

There are several patches from Mel Gorman in 3.11, which really made a
difference for me. So unless you tested with >= 3.11 you should probably
re-test.

> you may get a hoot out of, being a collectl user, is I have an xfs plugin
> that lets you look at a ton of xfs stats either in realtime or after the
> fact just like any other collectl stat.  I just havent' added it to the kit
> yet.


Hmm, I currently don't have good a test system for that. I'm working on
an entirely different project now and while this is also a parallel file
system, it does not have a linux file system in between, but has its own
(log rotated) layout.


Cheers,
Bernd
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      reply	other threads:[~2016-01-25 19:33 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-06 15:15 xfs and swift Mark Seger
2016-01-06 22:04 ` Dave Chinner
2016-01-06 22:10   ` Dave Chinner
2016-01-06 22:46     ` Mark Seger
2016-01-06 23:49       ` Dave Chinner
2016-01-25 16:38         ` Mark Seger
2016-02-01  5:27           ` Dave Chinner
2016-01-25 18:24 ` Bernd Schubert
2016-01-25 19:00   ` Mark Seger
2016-01-25 19:33     ` Bernd Schubert [this message]

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