Re: [MooseFS-Users] Chunkserver is also a client

[Valeri G. <ga...@ki...>]

On Tue, May 3, 2016 9:49 pm, Michael Tinsay wrote:
> Hi.
> I've been meaning to ask this for some time now.
> My current setup now is MooseFS 2.x with 1 Master, 1 Metalogger, 3
> Chunkservers, and all files have copies=3 so that all chunkservers will
> each have a complete set of chunks.  There are >5 clients connecting to
> this setup.
> Now, suppose that in one of the chunkservers, I mount mfs' root directory
> and start copying files to an external USB hard drive.
> My question is: will the chunkserver retrieve chunks from the other
> chunkservers for the files I'm copying?  Or does the mfs client code
> contain logic to determine that the chunks needed are available locally
> and, thus, all chunks are read locally which would in theory make the
> copying process go as fast as it could.

Not an answer, just a thought. You can measure it. Take really good USB-3
drive, or just copy to some fast internal filesystem, time what it takes.
Then repeat the same after throttling network interface down (simple thing
is just to put 10 mbps switch or hub between your 1 gbps ethernet port of
your server and 1 gbps port of switch it normally is connected to).

But I would like to hear the answer too, thanks for great question!

Valeri

>
> --- mike t.
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++++++++++++++++++++++++++++++++++++++++
Valeri Galtsev
Sr System Administrator
Department of Astronomy and Astrophysics
Kavli Institute for Cosmological Physics
University of Chicago
Phone: 773-702-4247
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