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NTP security update

Posted October 27, 2015 - permalink

Be aware of a recent NTP security update. Details can be found here:

It does not appear as serious as some of the previous NTP issues, but does highlight some vectors that could potentially be used to affect your clock. If you are running auto-updates, you likely already have the fixed version of the NTP packages. If not, you may run “yum update ntp ntpdate” to get the latest versions. The patched version of ntp is 4.2.6p5-5. No updates are required to any of the perfSONAR packages.

perfSONAR Toolkit congestion control bugfix update

Posted October 14, 2015 - permalink

A patch for the perfSONAR Toolkit has been released that fixes a long-standing bug in how the TCP congestion control algorithm is set. The bug is that the TCP congestion control algorithm is always set to “reno”, regardless of the state of NDT or NPAD. The intended behavior is that if NDT or NPAD are enabled, the algorithm is set to “reno”, otherwise it is set to “htcp”. In general, performance will be significantly worse with reno, but is required for NDT and NPAD since they assume specific reno behavior in their heuristics.

This has been corrected, so those of you not running NDT or NPAD may notice a significant increase in your throughput results once you install the patch. Please note that this bug was NOT introduced in the latest 3.5 release and dates back at least to the 3.4 release. For those of you still running either NDT/NPAD it may be a good time to review your use of these tools and whether enabling them is worth the associated performance hit. We strongly suggest not running NDT/NPAD on the perfSONAR host that you use for regular testing, and recommend using a separate, dedicated host for NDT instead.

For those running auto-updates, you should have the patch shortly. To manually update run the following:

yum update perl-perfSONAR_PS-Toolkit*

You will know if you have the patch if the toolkit version on your web interface is set to

perfSONAR 3.5 Deployment Trend

Posted October 2, 2015 - permalink

Adoption of perfSONAR 3.5 has been quick, aided by the automatic update procedure now available within the toolkit software.  The following chart shows this trend starting the day before the release was pushed to the software mirrors:

  Oct 2 Oct 1 Sept 30 Sept 29 Sept 28 Sept 27
perfSONAR Deployment Trends
3.3.x 126 120 124 134 142 142
3.4.x 296 351 373 780 1150 1143
3.5.x 1052 987 957 720 47 47

This trend can also be viewed graphically:

perfSONAR 3.5 now available

Posted September 28, 2015 - permalink

The final version of perfSONAR 3.5 is now available. Existing users may run "yum update" to get this new release. Alternatively, if you have automatic updates enabled, you should get the update within 24 hours. It is recommended, though not required, that you reboot the host after the update to ensure you are running the latest packages and kernel. For new Toolkit installs, you may find our ISOs at the following link:

For more information on install options, updating and using the software please see

About 3.5:

Version 3.5 is intended to be an important first step toward increasing the usability, automation and ease of large-scale deployments for existing perfSONAR users. Read more here: Some specific changes in this release include the following:

  • A brand new web interface that addresses many of the UI concerns voiced in the community over the past few years. You will be presented with this interface the next time you visit the toolkit after the update is applied. See the documentation for some screenshots of the new interface: For this release you will also be able to visit the previous interface by navigating to http://hostaddress/toolkit-old in your web browser.
  • Support for alternative installation methods to the Toolkit ISO on both CentOS and Debian/Ubuntu. This allows for more flexibility in deployment, especially for large deployments and/or those running lower cost hardware. See in our documentation for more details.
  • Enhanced central management and “auto-configuration” features to aid in the deployment of a large number of hosts. See our documentation at for more details.

In addition to above there are of course the usual round of bug fixes and performance improvements that go hand-in-hand with a release. Thank you to all in the community who helped us to identify and solve those over the past few months. Full release notes can be found at

Also, please take this chance to review our hardware advice page: Version 3.5 should NOT introduce any significant hardware resource requirements over version 3.4, but as test meshes continue to grow many of the requirements such as memory, are becoming “stricter” minimum requirements than in the past so this is a good opportunity to verify your setup. In particular, note that we recommend a minimum of 4GB of RAM for a perfSONAR Toolkit host.