perfSONAR User Q&A and Other Discussion

[Brian Candler <>]

On 03/04/2017 20:02, Andrew Lake wrote:

- If you have a single-core CPU, we recommend disabling auto-updates. Our testing shows that the combination of running CPU intensive throughput tests and/or OWAMP tests with high write activity to the measurement archive on top of the new scheduling system does not perform as desired beyond more than a few tests. Such a setup may be fine if you plan to use it as an ad-hoc tester as opposed to for use with dedicated measurements.  It is worth noting here that this is below the minimum recommendations for 3.5.

- If your host has a CPU with two cores but the clock speed is below 2GHz or less than 4 GB of RAM, we recommend using your best judgement. If you are running a couple dozen tests or less you are likely fine with regards to CPU. 4GB has been the memory recommendation for many years on the toolkit, and if you are below that and running a bundle without the measurement archive you may be fine as well. If you are running on less than 4GB with a local measurement archive, we encourage you to add memory or disable auto-updates (and we would have recommended this the last few releases as well).

Sad that perfsonar isn't going to work well on smaller boxes any more, especially since the new version "contains numerous performance optimizations" [^1]

I'd like to understand the issue a bit more.  Is this the same as the issue of "On sufficiently loaded hosts it is not uncommon for archiving to fall behind"?  If so, is this an issue which is better with SSD than HDD, or is it really just about CPU utilisation? Is esmond now processing the data more, or has the on-disk format changed?

Have these changes resulted in some benefits in terms of how the data can be queried or summarised, and if so, what are they?

Fortunately, it looks like the nodes I've been deploying (NUC5CPYB - 2-core Celeon / 1.6GHz / 8GB) will probably be OK for a while.  But I've also had some VMs with 2GB RAM and local MAs which were fine with a few tests, and I'm a bit concerned about those.

Regards,

Brian.

[^1] http://www.perfsonar.net/release-notes/version-4-0-rc1/