perfSONAR User Q&A and Other Discussion

[Daniel Doyle <>]

On Jun 19, 2015, at 5:02 PM, Hyojoon Kim <> wrote:

Hello, 

I just started to look at perfSONAR, I have several noob questions. I hope they are not too stupid questions :-P

The questions relate to using measurement archive (MA), MaDDash, and central mesh configuration setup. 

1. Can an MA host server be a MaDDash server and a central mesh configuration server, altogether at the same time? Maybe also a host with perfSONAR Toolkit installed? If possible, is this a good choice of design? I am asking because we have one host that we want to use as a measurement point, configuration server, visualization server, and as a place to store measurement data because it has lots of storage space. 

Yes, you can do this. In terms of whether it's a good choice of design, I expect you will get different answers from different people for different reasons. :)

As long as the host is suitably provisioned such that it's not maxed out on CPU or swapping on memory or anything like that, you should be fine. The answer to "suitably provisioned" depends on how busy it's going to be - how many regular tests are running, how many users are pulling data from the MA, etc.

2. Does MaDDash make sense even if all the data are stored in your central server?  

Yes. Storing data in a central server only means that the result data is centralized. The results store what the src/dst were, not where they were stored. The tests still happen on their respective endpoints and are documented as such, they just reported the results back to the central server. MaDDash reports on the results of these tests, so whether it's pulling in data from a hundred different MAs or just a single one the end result to the user is the same. It will show the correct src/dst information even if stored in a central MA.

3. Related to MA setup and mesh configuration, the ESnet example seems to have  MA configuration lines here: 

https://github.com/esnet/esnet-perfsonar-mesh/blob/master/conf/esnet-nextgen-meshconfig.conf#L32

It only defines type, read_url, and write_url. However, in this document, it says the measurement hosts (MHs) have to setup database, username, password, etc as well as the summary blocks at "/opt/perfsonar_ps/regular_testing/etc/regular_testing.conf".

http://docs.perfsonar.net/multi_central_MA.html

Are these two different configuration files? What is the point of putting read_url and write_url in the meshconfig when each MHs are going to put information about the URL address anyway in its own regular_testing.conf? 

The read/write URLs I believe are an artifact from an earlier measurement archive before Esmond. In the Esmond world (perfsonar 3.4+), they're going to wind up being the same URL.

The regular_testing.conf file is derived from the mesh config when used in a mesh configuration. Basically you set up the mesh config and put it into a web accessible place. Various clients download it and convert that into a regular_testing.conf file for all the bits that are important to that host. The regular testing process then reads that and performs the test as if you had configured it from the UI. Since all the clients are doing this, they all wind up testing to eachother and end up making a mesh.

Thanks,

Joon 

Dan Doyle

GlobalNOC Software Developer

1-812-856-3892

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