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Q: Does my machine have to meet the System Requirements?
A: There is nothing on the perfSONAR Toolkit that will prevent systems that do not meet the requirements from starting. Erroneous or inaccurate behavior is possible if the hardware cannot support the measurement tools. Performance considerations do favor meeting or exceeding the minimum guidelines.
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-Q: The Services screen shows many services in the non-running state when first started, what is wrong?
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Q: The Services screen shows many services in the non-running state when first started, what is wrong?
A: Services should start right away. It may be an indication of an installation problem. See Reading Log Files for information on where to look for more information.
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Q: I do not see my service in the directory of services, where is it?
A: Much like DNS, the information that will populate the Lookup Service will take time to propagate. Please allow some time (e.g. a few hours) before your service will be fully visible. If it stil does not appear, you may want to look in lsregistrationdaemon.log for errors.
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Q: How do I disable global registration?
A: The following commands will stop, and disable, this service:
systemctl stop perfsonar-lsregistrationdaemon
systemctl disable perfsonar-lsregistrationdaemon
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-Q: Which repository addresses will be used to get updates to the perfSONAR software?
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Q: Which repository addresses will be used to get updates to the perfSONAR software?
A: By default, the perfSONAR repo points at a mirror list hosted by software.internet2.edu. In this mirror list is linux.mirrors.es.net. In order to use the default configuration you will need to allow access to software.internet2.edu so you can grab the mirrorlist. After that, the packages can be downloaded from any of the sites listed which includes linux.mirrors.es.net, software.internet2.edu, and a few other places. You should be able to get away with just opening up access to software.internet2.edu (so it can get the mirror list) and linux.mirrors.es.net (so you can get the packages).
Those should be the only places you need as linux.mirrors.es.net also has a mirror for all the base CentOS packages.
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-Q: I am trying to run perfSONAR on low-cost hardware (e.g. raspberry pi, etc.). Where should I start?
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Q: I am trying to run perfSONAR on low-cost hardware (e.g. raspberry pi, etc.). Where should I start?
A: There are numerous hardware platforms that have emerged that are an attractive option for use in network performance measurement. The perfSONAR collaboration does not recommend, nor support, the use of perfSONAR on low-end, ARM-based hardware such as the Raspberry PI. It has been shown that it is difficult to distinguish network issues, from host issues, on these devices. In particular, we do not recommend these devices for testing throughput. Use of latency based tools (Ping, OWAMP) is possible provided that an accurate clock source is available.
For more information, see perfSONAR on Low-cost Hardware.
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-Q: I am running a small node, and seeing a lot of IO. What is going on?
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Q: I am running a small node, and seeing a lot of IO. What is going on?
A: Some users report abnormalities on their small nodes related to I/O activity (e.g. iostat reports long w_await times - sometimes measured in multiple seconds). These coincide with intervals of testing, in particular related to OWAMP.
Deeper investigation found that there is too much I/O going on: syslogd and systemd-journald processing syslog messages from “owampd and powstream” in “/var/log/messages”, sometimes up to 30-40 syslog messages per second depending on the testing configuration of a host. Given that small nodes are based on flash memory, changes should be made to ensure a more balanced approach to logging:
Do journaling on memory by editing “/etc/systemd/journald.conf”.
Make option “Storage=volatile” instead of the default “Storage=auto”. Make sure to limit the maximum usage of memory for journaling. You can do this by fiddling with “RuntimeKeepFree” and “RuntimeMaxUse” options.
Don’t restart the journaling service (i.e., don’t do “systemctl restart systemd-journald”). Do an OS reboot instead.
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-Q: Where can I find more resources regarding timekeeping for VMWare Virtual Machines?
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Q: Where can I find more resources regarding timekeeping for VMWare Virtual Machines?
A: VMWare has two resources worth reading:
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-Q: How do you upgrade a perfSONAR node from Debian 7 to Debian 9
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Q: How do you upgrade a perfSONAR node from Debian 7 to Debian 9
A: Because of systemd, upgrading a host running perfSONAR on Debian 7 to Debian 9 is better done in multiple steps as described bellow:
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-Q: Why can’t my Debian/Ubuntu host find ping?
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Q: Why can’t my Debian/Ubuntu host find ping?
A: Run apt reinstall iputils-ping to fix the issue. This was caused by a bug in the paris-traceroute package that installed a non-standard version of ping that required sudo. This was removed in perfSONAR 5.0.5 which left some systems without a ping command.
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Q: Where are the relevant logs for perfSONAR services?
A: Please see Reading Log Files for more information.
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-Q: How do I enable log compression with logrotate.conf?
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Q: How do I enable log compression with logrotate.conf?
A: Sometimes, log files can grow bigger and consume disk space even before their rotation. Logrotate is a system utility installed by default and is configured to handle log rotation for all installed packages and applications. In order to enable system-wide log files compression change default settings in /etc/logrotate.conf and uncomment compress option. This implies that rotated files will be compressed with log files having a .gz file extension.
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-Q: Can I use a firewall?
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Q: How many NTP servers do I need, can I select them all?
A: It is recommended that 4 to 5 close and active servers be used. The Select Closest Servers button will help with this decision. Note that some servers may not be available due to routing restrictions (e.g. non-R&E networks vs R&E networks - a common problem for Internet2 and ESnet servers).
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-Q: When setting up a dual homed host, how can one get individual tests to use one interface or another?
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Q: How do I change the MTU for a device?
A: Changing the MTU on your perfSONAR host should only be done if the underlying network supports the chosen size. Please work with your local network staff before making this change on any host.
You can view the MTU of your network devices by executing the /sbin/ifconfig command.
To temporarily change the MTU for a device, you use the ifconfig command and specify the device and the new MTU. For example: ifconfig eth0 mtu 9000 up
To make these changes permanent you need to modify the specific devices configuration file. These files are in /etc/sysconfig/network-scripts/ and have names like ifcfg-eth0 for the device eth0 and ifcfg-eth1 for eth1.
For example you could add the line MTU=”9000” for IPv4 or IPV6_MTU=”9000” for IPv6 to /etc/sysconfig/network-scripts/ifcfg-eth0.
After making the changes you need to restart the network services by running the command ‘service network restart’ as root.
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Q: How do I change the SSL certificate used by the web server?
A: The toolkit by default generates a self-signed SSL certificate that it configures for use with the Apache web server. Some users may desire to replace this certificate with a certificate signed by a certificate authority (CA).
You may also need to replace the certificate due to a problem sometimes encountered with browsers not accepting the self-signed certificate. You may see an error like the following:
HOST uses an invalid security certificate.
@@ -268,9 +268,9 @@ Q: How do I change the SSL certificate used by the web server?here.
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Then Restart the host. You can now assign an IPv6 address.
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Q: How do I setup a perfSONAR node to have two interfaces on the same subnet?
A: This can be accomplished by setting the following items in sysctl:
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Q: My host was impacted by Linux security issue (Shellshock/Heartbleed/etc.). What should I do?
A: Please check the RedHat vulnerability archive or the Debian security list for updates, and upgrade your system as soon as the update is available.
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-Q: How to get rid of “There isn’t a perfSONAR sudo user defined” message?
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Q: How to get rid of “There isn’t a perfSONAR sudo user defined” message?
A: The best option is to add a non-root user to the pssudo group. If you have another method of handling sudo users, comment out the lines in /etc/profile.d/add_psadmin_pssudo.sh. Do not remove the file entirely, just modify it, otherwise it will get restored on update.
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-Q: Is it possible to use non-intel SFP+ optics in the Intel X520-SR2 NIC?
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Q: Is it possible to use non-intel SFP+ optics in the Intel X520-SR2 NIC?
A: The ixgbe driver has an option to allow alternative optics:
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-Q: How can I tune a Dell server for a high throughput and low latency?
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Q: What is PTP?
A: PTP is the Precision Time Protocol, also known as IEEE 1588, a more-accurate successor to the Network Time Protocol which as been used for many years to discipline the clocks in general-purpose computers. Under ideal conditions, PTP can discipline a clock to within a few microseconds of UTC. Compare this with NTP, which typically has accuracy of about a millisecond when used with clocks on the Internet and 100 microseconds or less when using a stratum-1 clock in a LAN environment.
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-Q: What is required to use PTP in my network?
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Q: What is required to use PTP in my network?
A: Unlike NTP, which provides satisfactory operation using software clients and a pool of servers usually on the Internet, running PTP requires specialized equipment:
Clocks. For production-grade service, PTP requires a minimum of two grandmaster clocks. These are dedicated hardware appliances that use the Global Positioning System to recover accurate time and a high-precision oscillator for holdover during periods when GPS is not available. At this writing, base model clocks cost about US$2,500 each.
Network Infrastructure. PTP requires that all network elements between the grandmaster and slaves be capable of functioning as a boundary clock. This is a feature typically found on high-end routers and switches designed for use in low-latency applications.
Network Interface Cards. Interfaces in the slave system require hardware support for the timestamping that makes PTP work accurately. While software-only PTP clients exist, they may suffer inaccuracies induced by the vagaries of running under a general-purpose operating system and provide inaccurate results when testing latency in a LAN environment.
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-Q: Does perfSONAR support PTP?
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Q: Does perfSONAR support PTP?
A: Not at this time. The prohibitive cost of deploying PTP makes it unlikely to be used widely enough to merit adding support. The current perfSONAR code contains assumptions that the clock is disciplined by NTP and would need to be modified for other protocols.
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-Q: When trying to migrate from a CentOS 6 to a CentOS 7 host I receive pg_dump error. How to fix it?
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Q: When trying to migrate from a CentOS 6 to a CentOS 7 host I receive pg_dump error. How to fix it?
A: Using a script that will create a backup/restore of relevant configuration files and measurement data may generate pg_dump error failing to create pScheduler backup. This happens when you have both postgresql 8 and postgresql 9 installed, but pscheduler backup script expects only postgresql 9. This can be patched by editing /usr/libexec/pscheduler/commands/backup:
Remove line:
pg_dump \
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Rerun the backup script.
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-Q: How do I join the perfSONAR Collaboration?
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