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- I see sysctl differences between the natest-arc servers and the na-arc servers. Here is a diff of /etc/sysctl.d/99-nrao.conf on natest-arc-1 and na-arc-5
< #net.ipv4.tcp_tw_recycle = 1
---
> net.ipv4.tcp_tw_recycle = 1
22,39d21
< net.ipv4.conf.all.accept_redirects=0
< net.ipv4.conf.default.accept_redirects=0
< net.ipv4.conf.all.secure_redirects=0
< net.ipv4.conf.default.secure_redirects=0
<
< #net.ipv6.conf.all.disable_ipv6 = 1
< #net.ipv6.conf.default.disable_ipv6 = 1
<
< # Mellanox recommends the following
< net.ipv4.tcp_timestamps = 0
< net.core.netdev_max_backlog = 250000
<
< net.core.rmem_default = 16777216
< net.core.wmem_default = 16777216
< net.core.optmem_max = 16777216
< net.ipv4.tcp_mem = 16777216 16777216 16777216
< net.ipv4.tcp_low_latency = 1If I set net.ipv4.tcp_timestamps = 0 on na-arc-5, the wget download drops to nothing (--.-KB/s).
- If I set all the above sysctl options, execpt net.ipv4.tcp_timestamps, on all five na-arc nodes, wget download performance doesn't change. It is still about 32KB/s. Also I still zeeo ZeroWindow packets.
- Try rebooting VMs after making changes?
- What are the sysctl settings on the VM hosts?
- Does having net.ipv4.conf.all.accept_redirects = 1 and/or net.ipv4.conf.all.forwarding = 0 set on naasc-vs-5 cause problems? They are set the other way on naasc-dev-vs, naasc-vs-1, naasc-vs-3, and naasc-vs-4
- I see ZeroWindow packets sent from na-arc-5 to nangas13 while downloading a file from nangas13 using wget. This is na-arc-5 telling nangas13 to wiat because its network buffer is full.
- Is this because of qdisc pfifo_fast? No. krowe changed eth0 to *qdisc fq_codel* and still seeing ZeroWait packets.
- Why does almaportal use ens3 while almascience uses eth0?
- What if we move the rh-downloader container to a different node? In fact walk it through all five nodes and test.
- Why do I see cv-6509 when tracerouting from na-arc-5 to nangas13 but not on natest-arc-1
[root@na-arc-5 ~]# traceroute nangas13
traceroute to nangas13 (10.2.140.33), 30 hops max, 60 byte packets
1 cv-6509-vlan97.cv.nrao.edu (10.2.97.1) 0.426 ms 0.465 ms 0.523 ms
2 cv-6509.cv.nrao.edu (10.2.254.5) 0.297 ms 0.277 ms 0.266 ms
3 nangas13.cv.nrao.edu (10.2.140.33) 0.197 ms 0.144 ms 0.109 ms[root@natest-arc-1 ~]# traceroute nangas13
traceroute to nangas13 (10.2.140.33), 30 hops max, 60 byte packets
1 cv-6509-vlan96.cv.nrao.edu (10.2.96.1) 0.459 ms 0.427 ms 0.402 ms
2 nangas13.cv.nrao.edu (10.2.140.33) 0.184 ms 0.336 ms 0.311 ms
- Why does natest-arc-3 have ens3 instead of eth0 and why is its speed 100Mb/s?
- virsh domiflist natest-arc-3 shows the Model as rtl8139 instead of virtio
- When I run ethtool eth0 on nar-arc-{1..5} natest-arc-{1..2} as root, the result is just Link detected: yes instead of the full report with speed while na-arc-3 shows 100Mb/s.
- Why do iperf tests from natest-arc-1 and natest-arc-2 to natest-arc-3 get about half the performance (0.5Gb/s) expected especially when the reverse tests get expected performance (0.9Gb/s).
- Is putting the production swarm nodes (na-arc-*) on the 10Gb/s network a good idea? Sure it makes a fast connection to cvsan but it adds one more hop to the nangas servers (e.g. na-arc-1 -> cv-nexus9k -> cv-nexus -> nangas11)
- When I connect to the container acralmaprod001.azurecr.io/offline-production/rh-download:2022.06.01.2022jun I get errors like unknown user 1009 I get the same errors on the natest-arc-1 container.
- Does it matter that the na-arc nodes are on 10.2.97.x, their VM host is on 10.2.99.x while the natest-arc nodes are on 10.2.96.x and their VM hosts (well 2 out of 3) are also on 10.2.96.x? Is this why I see cv-509.cv.nrao.edu when running traceroute from the na-arc nodes?
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