The key to this is to minimize the time that the data and mapfile are
potententially out of sync or the time a file might be being updated so
that it is in a state of flux that might cause an error if a request
tries to read the file while it is being updated.
I have managed this in the past with parallel data trees and a symbolic
link on Linux.
/path/to/data/
/path/to/data/imagesA
/path/to/data/imagesB
/path/to/data/images -> imagesA or imagesB
the map file points to /path/to/data/images and that is a symbolic link
to either imagesA or imagesB, for example lets say imagesA
So the update process would be something like:
# sync your A and B trees
rsync -s imagesA/* imagesB/.
# update the images in imagesB and the mapfile in imagesB
# make imagesB live
(cd /path/to/data/; rm images; ln -s imagesB images)
# if you want to rollback to imagesA
(cd /path/to/data/; rm images; ln -s imagesA images)
Hope this helps,
-Steve W
Dan Little wrote:
Yes, it's a matter of how you do your data management.
Generally, if you're using MapServer in CGI mode you can update the
data, or the mapfile, and the next time a request comes in, it will
see the updated version of your image.
----- Original Message ----
From: Björn Harrtell <bjorn.harrt...@gmail.com> To:
mapserver-users@lists.osgeo.org Sent: Mon, December 7, 2009 3:11:36
PM Subject: [mapserver-users] Dynamically update layers without
service interruption
Is it possible to dynamically add and/or update layer definitions
that also might involve updates to the underlying data without
*any* service interruption? I'm primarily interested in this use
case when using raster layers.
I have indications that service interruptions can happen but cannot
verify yet. I found
http://www.mapserver.org/development/rfc/ms-rfc-44.html#rfc44
describing the feature of dynamic updates (I assume?) but no
mention about if service interruption can be expected and/or how to
avoid it.
Regards,
Björn Harrtell _______________________________________________
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