[RFC 004] Operation Review Comment 10

UCI (filled out by SJSK based on telephone conversation 29Mar05)

Review of DAP2 operational experience:

1. Describe in a sentence or two your overall operational experience related to DAP2

Use of DAP client for 6-7 years. Only recently has he set up a server. Accesses climate data from NOAA CDC. He’s getting set up to serve data pulled from supercomputer sites and operated on with his netCDFOperator (NCO) suite.

What kinds of DAP2 systems do you have experience with?

OPeNDAP netCDF server

How long have you been using DAP2 operationally?

Server side – about a year.

2. What types of applications do you use DAP2 systems for?

See above

Are the DAP2 systems applicable to your applications? (e.g., Do they work well with the data types and data manipulations in your application?)

yes

1. How many of your applications use DAP2? NA. Zender is a tool developer, not a data provider

1. Why do you choose to use DAP2 systems over other systems for your applications?

Easy to implement, free, open source, developers are responsive

1. What alternative technologies did you consider?

There are some technologies now coming online, but they weren’t ready when participant started out. These are: netCDF/L from LoCI (http://loci.cs.utk.edu/) and Grid Access Data Service (http://forge.nesc.ac.uk/projects/gads/).

4. Are the DAP2 systems easy to use?

As a client it is very easy to use. It is a painless way to link applications to data sources. However, setting up a server is problematic on anything but linux boxes. Participant wishes to implement it on AIX or SOLARIS boxes, which are currently the more common OSs for supercomputer centers, but unfortunately this is not well supported. Specifically, Participant is keen on using native compilers, but there is no easy way to modify the installation to use alternative libraries. OPeNDAP requires 6 different libraries to be installed. The configuration mechanism for building is very primitive. Big area for improvement.

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

No.

5. Does the performance of the DAP2 systems you have experienced meet your requirements?

   1. Have your bandwidth issues changed since you have been using DAP2 systems?

Don’t know yet. They will be doing some benchmarking in the coming year to see how NCO performs with and without the DAP2 interface.

6. What operational challenges do the DAP2 systems present?

   1. How has the use of DAP2 affected your systems administration workload?

Other than the installation challenges mentioned above, none so far.

7. 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?

      1. Total data volume

      2. Total number of data files

      3. Percentage of data volume

      4. Percentage of data files

NA

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?

      1. Total number of DAP2 users

      2. 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?

NA – Participant is not currently a data provider, and NCO does not have “spyware” to record when people access data using OpenDAP.