On Tue, Nov 7, 2017 at 3:05 PM, Steve Omondi <steve.omo...@ramani.co.ke>
wrote:
> I have 6 Geoservers + Embedded GWC spread on two VMs 3 each. Each running
> on separate Tomcat. All the Six Geoserver are running behind Apache HTTPD
> proxy Balancer. I tried tuning the Java Process setting to optimum.
>
> On the other hand I had a single Geoserver+ Embedded GWC.
>
> On performing tests, The 6 Geoserver are 4-6 time slower than the Single
> Geoserver while rendering a layergroup of HR Aerial Imagery on Openlayers
> client.
>
> I made a list of the configuration differences between the clustered
> Geoservers and the Single Geoserver and some of the items are;
>
> - I use Authkey for Authentication in the Clustered Geoservers with a
> JDBC Role Service - so maybe every tile request has to perform
> authorization by querying the database and all those processes may slow the
> request.
>
>
This certainly adds work, queries to databases are expensive (how much so,
depends a lot on your configuration, network, indexes and the like)
>
> - JDBCConfig is used in the clustered Geoserver as opposed to XML
> Catalog in the Single Geoserver; same as above the query process could be
> slowing requests.
>
> Yes, this is well known, see this proposal I made at the beginning of
2017, it contains some performance numbers too:
https://github.com/geoserver/geoserver/wiki/GSIP-155
I cannot tell you how much of those 80ms are weighting on WMTS calls
hitting already cached tiles on the embedded GWC, but I'm confident part of
it will be there.
>
> - The fact that *GWC Directory and Diskquota are clustered could be an
> issues*; write/access speed of the remote GWC directory seems to me as
> a cause of slow rendering of tiles and as so it tops my list of culprits.
>
> That depends a lot on the network file system in use.
> The third point is the source of my motivation to run GWC as standalone
> in front of the Geoserver Cluster proxy. The have the GWC Blobstore closer
> instead of a network drive.
>
> Can you elaborate what you mean by "as efficient and
> fast"?
>
> My experience with the Integrated GWC (Six Instances of them which do not
> share workload) is definitely slower as I've mentioned 4 -6 times slower
> that a single GWC.
>
Are you talking about serving cached tiles or tiles that need to be built
on the fly?
>
> In fact I have stopped one VM and move the Tiles (GWC dir) to a local
> directory in the same machine as the Geoservers but still slower than one
> Geoserver.
>
Yeah, the two common topologies are:
- Shared network storage, mostly read only, pre-seeded on some other,
non online machine
- One tile storage per network node, non shared, especially useful for
data changes a lot
I'd love to see a local storage option that allows picking tiles from other
nodes via some clustering technology (e.g., hazelcast distribution),
merging the benefits of the two world but... it's missing funding to be
developed
Cheers
Andrea
==
GeoServer Professional Services from the experts! Visit http://goo.gl/it488V
for more information.
==
Ing. Andrea Aime
@geowolf
Technical Lead
GeoSolutions S.A.S.
Via di Montramito 3/A
55054 Massarosa (LU)
phone: +39 0584 962313
fax: +39 0584 1660272
mob: +39 339 8844549
http://www.geo-solutions.it
http://twitter.com/geosolutions_it
AVVERTENZE AI SENSI DEL D.Lgs. 196/2003
Le informazioni contenute in questo messaggio di posta elettronica e/o
nel/i file/s allegato/i sono da considerarsi strettamente riservate. Il
loro utilizzo è consentito esclusivamente al destinatario del messaggio,
per le finalità indicate nel messaggio stesso. Qualora riceviate questo
messaggio senza esserne il destinatario, Vi preghiamo cortesemente di
darcene notizia via e-mail e di procedere alla distruzione del messaggio
stesso, cancellandolo dal Vostro sistema. Conservare il messaggio stesso,
divulgarlo anche in parte, distribuirlo ad altri soggetti, copiarlo, od
utilizzarlo per finalità diverse, costituisce comportamento contrario ai
principi dettati dal D.Lgs. 196/2003.
The information in this message and/or attachments, is intended solely for
the attention and use of the named addressee(s) and may be confidential or
proprietary in nature or covered by the provisions of privacy act
(Legislative Decree June, 30 2003, no.196 - Italy's New Data Protection
Code).Any use not in accord with its purpose, any disclosure, reproduction,
copying, distribution, or either dissemination, either whole or partial, is
strictly forbidden except previous formal approval of the named
addressee(s). If you are not the intended recipient, please contact
immediately the sender by telephone, fax or e-mail and delete the
information in this message that has been received in error. The sender
does not give any warranty or accept liability as the content, accuracy or
completeness of sent messages and accepts no responsibility for changes
made after they were sent or for other risks which arise as a result of
e-mail transmission, viruses, etc.
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
Geoserver-users mailing list
Please make sure you read the following two resources before posting to this
list:
- Earning your support instead of buying it, but Ian Turton:
http://www.ianturton.com/talks/foss4g.html#/
- The GeoServer user list posting guidelines:
http://geoserver.org/comm/userlist-guidelines.html
Geoserver-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/geoserver-users
