[mapguide-internals] MapGuide RFC 42 - Remove Support Servers

[Trevor Wekel]

Hi Zac,

MapGuide supports rudimentary load balancing and session affinity as described in "RFC3 - Session Affinity".  A single web extensions install can round robin between the site servers on multiple machines.

http://trac.osgeo.org/mapguide/wiki/MapGuideRfc3


The MGP's only contain Library:// and Site:// resources and their associated managed data.  Unmanaged folders and the tile cache are not included in the MGP.

You are right on track with the rsync and hot backup.  If the site servers are running an identical configuration (directory paths, etc), then any sort of directory replication scheme would form the basis of site to site replication.  If you have $$$ for a SAN or NAS then replication becomes even easier (assuming everything is unmanaged data hosted on the SAN/NAS):

"Master": Hot back up the repository from local disk to the SAN/NAS
"Slave(s)": Shut down MapGuide Server
"Slave(s)": Restore hot backup from SAN/NAS to local disk
"Slave(s)": Restart MapGuide Server
Done.

All the data is on the SAN/NAS so it does not have to be replicated.  This becomes very interesting if you don't have terabytes of data and can afford to stick it all on an SSD (solid state disk).

Thanks,
Trevor


-----Original Message-----
From: mapguide-internals-bounces at lists.osgeo.org [mailto:mapguide-internals-bounces at lists.osgeo.org] On Behalf Of Zac Spitzer
Sent: Thursday, December 06, 2007 4:10 PM
To: MapGuide Internals Mail List
Subject: Re: [mapguide-internals] MapGuide RFC 42 - Remove Support Servers

Ok it makes sense..... we will become more reliant on proxing a bit then.

MGP's don't include the tile cache tho do they? is that do-able? I wish WMS
would set a cache header...

I would be nice to be able to define a master site servers (including
unmanaged folders to be rsync-ed)
and be able to push the config out from one master site server...

should be pretty easy to script... hot back up the repository, rsync the
unmanaged folders & tilecache (would that work?),
shut down the slave site server, restore the hot back up, and bring it back
up.

z

On Dec 7, 2007 4:13 AM, Trevor Wekel <trevor.wekel at autodesk.com> wrote:

> Hi Zac,
>
> Since the configuration of site and support servers is no longer possible
> through the Site Administrator, this RFC effectively disables support server
> functionality.
>
> I agree having multiple site repositories makes data management for load
> balanced site servers more complex.  Packages (mgp files) can help alleviate
> this problem if a "production" and "dev/test" environment are set up.  Only
> the production setup would be load balanced.  Mgp's would be created in the
> "dev/test" environment and deployed to the production site servers using an
> mgp load.
>
> There are a couple of performance advantages to using load balanced site
> servers versus site and support servers:
>
> 1.  All service to service traffic remains in process on the local
> machine.
>
> A typical rendering service operation talks to the resource service and
> feature service.  In a site server / support server setup, all of this
> traffic will have to be serialized, transmitted over the wire, and
> de-serialized.  This incurs significant overhead.
>
> The only way to get good performance on site/support server setup is to
> have all of the services except resource service present on each support
> server.  This also means the managed and unmanaged data files (SDF, SHP,
> raster) must also be present on each support server.  So you end up
> performing the data replication manually.
>
> 2.  Multiple site servers provide multiple session repositories.
>
> This is significant for higher user loads because the users are evenly
> balanced over the available site servers.  It is similar to using a database
> cluster that does not perform replication.
>
>
> Does this help?
>
> Thanks,
> Trevor
>
> -----Original Message-----
> From: mapguide-internals-bounces at lists.osgeo.org [mailto:
> mapguide-internals-bounces at lists.osgeo.org] On Behalf Of Zac Spitzer
> Sent: Wednesday, December 05, 2007 6:24 PM
> To: MapGuide Internals Mail List
> Subject: Re: [mapguide-internals] MapGuide RFC 42 - Remove Support Servers
>
> "Load balanced site servers provide better scalability and easier
> setup than separate site
> and support servers. Furthermore, the site and support server concept
> is confusing for the user base."
>
> How will this affect server admin?.... the support server (calling it
> a Render Slave makes a lot more sense) approach
> means you only need to maintain and update one repository.
>
> Having to maintain 6 site servers instead of 5 support servers and one
> site server sounds like a backward step
> in terms of maintainability.
>
> Renaming the support servers to something that provides more insight
> into their function would be a good step.
>
> Also the RFC Title should specify that this is only at the MapGuide
> Site Administrator level
>
> ie "Remove Support Servers from MapGuide Site Administrator"
>
> Regards
>
> Zac
>
> On Dec 6, 2007 11:40 AM, Trevor Wekel <trevor.wekel at autodesk.com> wrote:
> > I would like to submit "MapGuide RFC 42 - Remove Support Servers" to the
> list for review and comment.  Please send your comments/concerns back to the
> list and I will respond.
> >
> > http://trac.osgeo.org/mapguide/wiki/MapGuideRfc42
> >
> > Thanks,
> > Trevor Wekel
> >
> > _______________________________________________
> > mapguide-internals mailing list
> > mapguide-internals at lists.osgeo.org
> > http://lists.osgeo.org/mailman/listinfo/mapguide-internals
> >
>
>
>
> --
> Zac Spitzer -
> http://zacster.blogspot.com (My Blog)
> +61 405 847 168
> _______________________________________________
> mapguide-internals mailing list
> mapguide-internals at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/mapguide-internals
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>



--
Zac Spitzer -
http://zacster.blogspot.com (My Blog)
+61 405 847 168
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