[RFC 004] Operation Review Comment 3

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).

I set up one plain DAP server (FreeForm) and several DAP processing servers (GrADS/Data server with different versions), and working on one DAP client (GrADS) for accessing (testing) data from both plain DAP servers and DAP processing servers. I also worked on ingesting metadata from DAP servers for supporting metadata search and DAP URL generation.

1. How long have you been using DAP2 operationally?

I used DAP2 only for research and testing purpose. Therefore, the direct answer to this question is zero time. For the same reason, some questions will be skipped because they cannot be answered accurately by me.

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?)��

Our applications are for internal research, especially, IT research related to DAP2. DAP2 does work with the data types we have and supports the data manipulations in our applications. I guess the question is on science applications. Therefore, no answers can be given by me to this question and to Question 3.

1. How many of your applications use DAP2?

                                                               i.      Total number of applications

                                                             ii.      Percentage of applications

3. Why do you choose to use DAP2 systems over other systems for your applications?
1. What alternative technologies did you consider?
4. Are the DAP2 systems easy to use?� (e.g., Is it hard to learn how to use DAP2 systems?)

Yes, plain DAP2 systems are easy to use as a client. The DAP2 servers are also easy to set up.

1. How has the use of DAP2 affected your user support workload?
4. 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?)

Yes. By using DAP2 system, one can save time on downloading a large data set. Most of time, the performance of DAP2 depends on the local network performance.

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?)
5. 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?)

DAP2 systems can be installed on systems with normal HW/SW configurations. The deployment and maintenance are easy. However, the operational performance depends on workload to particular systems.

1. How has the use of DAP2 affected your systems administration workload?
6. How well do the DAP2 systems scale to large numbers of simultaneous users, or to large datasets?
1. How much data does your DAP2 system handle in a typical month?

                                                               i.      Total data volume

                                                             ii.      Total number of data files

                                                            iii.      Percentage of data volume

                                                           iv.      Percentage of data files

8. Can you provide information on user statistics of your DAP2 systems?�

No.

1. How many users does your DAP2 system handle in a typical month?

                                                               i.      Total number of DAP2 users

                                                             ii.      Percentage of your overall users

2. Of the feedback you have received from your users on DAP2, what percentage is positive and what is negative?
3. How have the user statistics changed over time?