[Gluster-devel] replication client or server side

[Krishna Srinivas]

Vincent,

I am unable to see how are using unify in the latter config that you
plan to build.
Can you send the spec files so that they can be reviewed?

Kevan,
True, having the afr config on the server side will simplify the client spec.
But regarding the performance boost, it will be nice if we can come up
with speed values for the two configs.
In case someone gets time to test it out, do let is know :-)

Thanks
Krishna

On 10/16/07, Kevan Benson <kbenson at a-1networks.com> wrote:
> Vincent Régnard wrote:
> > Hi all,
> >
> > I am presently re-thinking the way we are using glusterfs 1.3.5 here. We
> > are doing replication (*3 with 3 bricks) on client side to produce a
> > small HA cluster. We are planning to extend the brick number. Drawing
> > that again and looking at some examples on the wiki doing it another way
> > (Kritical's tutorial), we are wondering wether doing the replication
> > (AFR) on the server side (glusterfsd) would be more suitable than doing
> > it on the client side ? Have you any experience or remark on that ? Does
> > this have performance impact in your opinion ?
> >
> > If replication is transfered to server side, we'll have to use
> > unification on client side to achive HA (and then obtain active
> > self-heal?). Is this latter configuration reasonable ?
> >
> >
> > Present configuration:
> >
> > Client stack:    FUSE
> >         PERFORMANCE TRANSLATORS (write-b/io-cache/io-thread)
> >         AFR
> >         CLIENT TRANSPORT
> >
> > Server stack:    SERVER TRANSPORT
> >         PERFORMANCE TRANSLATOR (io-thread)
> >         POSIX LOCKS FEATURE
> >         POSIX STORAGE
> >
> >
> > Planned configuration:
> >
> > Client stack:    FUSE
> >         PERFORMANCE TRANSLATORS (write-b/io-cache/io-thread)
> >         UNIFY
> >         CLIENT TRANSPORT
> >
> > Server stack:    SERVER TRANSPORT
> >         PERFORMANCE TRANSLATOR (io-thread)
> >         AFR
> >         POSIX LOCKS FEATURE
> >         POSIX STORAGE
> >
> > Vincent
>
> I find using AFR and Unify from the client yields a more robust config
> with respect to high availability, but using unify on the client
> complicates the configs and file storage (it necessitates splitting the
> share between a main and AFR split per server).  It may be possible to
> overload the AFR definitions to get around this, I haven't tried that
> yet.  It's also possible that tweaking the timeout values for the client
> and server to make the server timeout before the client might yield a
> more stable config.
>
> Performance wise, moving AFR to the server side will allow you structure
> the network for more performance, such as implementing a secondary
> network to handle all the AFR traffic.  As it is now (with you doing
> everything on the client), your writes are constrained to 1/3 of the
> total available network bandwidth, since you have to write each file 3
> times.  By moving the AFR to the server and implementing a second
> network to carry the AFR traffic, you could increase your theoretical
> network performance by 50% (if the AFR network is the same speed as the
> client network connection, and you want data stored on 3 servers).
>
> It seems like every other day I think of a new way to set up glusterfs.
> I have to say this is the most fun I've had with a software product in
> some time.  ;)
>
> --
>
> -Kevan Benson
> -A-1 Networks
>
>
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