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Re: Netcdf based web application and a question



Mark Rehbein wrote:

Hi John,
About a year ago you helped me with using the Netcdf java API you are developing. We finally have our web application which uses the netcdf api available for use so if you would like to see it then please visit the following URL: http://138.7.120.8:9555/sstatlas/do/gotoWelcome.do We have not advertised the url yet so please do NOT publish the url to the site just yet. I also have a question about the NCML dataset that we are using and its scalability. We have a netcdf file for each month of SST data which we aggregate with NCML and use as a dataset in the Netcdf java API. I have found that when the dataset is used, a file handle is created to each netcdf file defined in the aggregate. Obviously, if we have too many of these netcdf files in the aggregate the system will run out of file handles. I think our unix server can handle about 1024 file handles per process but these could potentially be used up if we are running multiple netcdf type applications on the single tomcat process. Thanks Mark

Hi Mark:

thanks for the update. looks pretty cool. have you studied the performance bottlenecks at all?

i am working on a new version of ncml aggregation that will let you specify number of open file handles. wont be done till next year sometime. its will be part of version 2.2 I may try to multithread it.

i'd like to hear about what features in ncml you are using, since i am making a new version and i am planning on dropping or modifying some of the tags.