[RFC 004] Operation Review Comment 11

Review of DAP2 operational experience:

NASA's Earth Science Data Systems Standards Process Group (SPG) is considering the Data Access Protocol, Version 2, (DAP2) for adoption as a community standard.  This is the second review of DAP2, this one focusing on its operation experience.  The questions below are provided to guide your feedback. You only need to answer questions applicable to you.  Please send comments to ese�rfc�004@spg.gsfc.nasa.gov. 

1. Describe in a sentence or two your overall operational experience related to DAP2 (e.g., scientific analysis; science users, server operation; database management; or data translation, etc).  What kinds of DAP2 systems do you have experience with?  (e.g., OPeNDAP netCDF server, OPeNDAP HDF server, OPeNDAP Matlab Toolkit, Ferret, GrADS, and etc).
1. How long have you been using DAP2 operationally?  We have supported OPeNDAP server access to our on-line data for four years, but we have no client applications using DAP.  On the server side we have deployed HDF and HDF-EOS servers as well as developed our own OPeNDAP-ESML server to support data formats not currently supported by OPeNDAP, e.g. Nexrad.
2. What types of applications do you use DAP2 systems for?  Are the DAP2 systems applicable to your applications? (e.g., Do they work well with the data types and data manipulations in your application?)   
1. How many of your applications use DAP2?  No client applications

                                                               i.      Total number of applications

                                                             ii.      Percentage of applications

3. Why do you choose to use DAP2 systems over other systems for your applications?  We added OPeNDAP servers to our data access alternatives because of involvement in the Federation.
1. What alternative technologies did you consider?  We also provide FTP/HTTP access to our on-line data, and WMS for selected products.
4. Are the DAP2 systems easy to use?  (e.g., Is it hard to learn how to use DAP2 systems?)  N/A
1. How has the use of DAP2 affected your user support workload?  Upfront effort to update GCMD DIFs with DODS URLs.   No change in customer support, because we have so few OPeNDAP users.
5. Does the performance of the DAP2 systems you have experienced meet your requirements?  (e.g., Does it take a long time to access data in DAP2 systems?) N/A
1. Have your bandwidth issues changed since you have been using DAP2 systems? (e.g., Have you seen increased bandwidth requirements because of increased data access or DAP2 overhead, decreased bandwidth requirements because of reduced data volume from subsetting, no impact on bandwidth because of low usage?)
6. What operational challenges do the DAP2 systems present? (e.g., Does it require advanced processing power, large amounts of memory, complex configuration, etc.? Are the systems easy to deploy and maintain?) From a server perspective, there has no notable increase of resource usage, nor configuration complexity resulting from the DAP servers that we have deployed. 
1. How has the use of DAP2 affected your systems administration workload? The impact on system administration has been minimal � mostly just initial installation and configuration.
7. How well do the DAP2 systems scale to large numbers of simultaneous users, or to large datasets?  While we do provide DAP server support for some large datasets, we have virtually no DAP clients/users that use that data through that protocol.
1. How much data does your DAP2 system handle in a typical month?

                                                               i.      Total data volume � 80 mb

                                                             ii.      Total number of data files � 50 files

                                                            iii.      Percentage of data volume � approximately 0.0002 %

                                                           iv.      Percentage of data files � approximately 0.01 %

8. Can you provide information on user statistics of your DAP2 systems? 
1. How many users does your DAP2 system handle in a typical month?

                                                               i.      Total number of DAP2 users  < 5

                                                             ii.      Percentage of your overall users < 2%

2. Of the feedback you have received from your users on DAP2, what percentage is positive and what is negative? No feedback received
3. How have the user statistics changed over time? No change