Hi Stefan, ahh OK, misunderstood your e-mail. It sounded like it was a custom profile, not a standard one shipped with tuned. Thanks for the clarification! ================= Frank Schilder AIT Risø Campus Bygning 109, rum S14 ________________________________________ From: Stefan Bauer <sb@plzk.de> Sent: Wednesday, May 22, 2024 12:44 PM To: ceph-users@ceph.io Subject: [ceph-users] Re: How network latency affects ceph performance really with NVME only storage? Hi Frank, it's pretty straightforward. Just follow the steps: apt install tuned tuned-adm profile network-latency According to [1]: network-latency A server profile focused on lowering network latency. This profile favors performance over power savings by setting |intel_pstate| and |min_perf_pct=100|. It disables transparent huge pages, and automatic NUMA balancing. It also uses *cpupower* to set the |performance| cpufreq governor, and requests a /|cpu_dma_latency|/ value of |1|. It also sets /|busy_read|/ and /|busy_poll|/ times to |50| μs, and /|tcp_fastopen|/ to |3|. [1] https://access.redhat.com/documentation/de-de/red_hat_enterprise_linux/7/htm... Cheers. Stefan Am 22.05.24 um 12:18 schrieb Frank Schilder:

Hi Stefan,

can you provide a link to or copy of the contents of the tuned-profile so others can also profit from it?

Thanks! ================= Frank Schilder AIT Risø Campus Bygning 109, rum S14

________________________________________ From: Stefan Bauer<sb@plzk.de> Sent: Wednesday, May 22, 2024 10:51 AM To: Anthony D'Atri;ceph-users@ceph.io Subject: [ceph-users] Re: How network latency affects ceph performance really with NVME only storage?

Hi Anthony and others,

thank you for your reply. To be honest, I'm not even looking for a solution, i just wanted to ask if latency affects the performance at all in my case and how others handle this ;)

One of our partners delivered a solution with a latency-optimized profile for tuned-daemon. Now the latency is much better:

apt install tuned

tuned-adm profile network-latency

# ping 10.1.4.13 PING 10.1.4.13 (10.1.4.13) 56(84) bytes of data. 64 bytes from 10.1.4.13: icmp_seq=1 ttl=64 time=0.047 ms 64 bytes from 10.1.4.13: icmp_seq=2 ttl=64 time=0.028 ms 64 bytes from 10.1.4.13: icmp_seq=3 ttl=64 time=0.025 ms 64 bytes from 10.1.4.13: icmp_seq=4 ttl=64 time=0.020 ms 64 bytes from 10.1.4.13: icmp_seq=5 ttl=64 time=0.023 ms 64 bytes from 10.1.4.13: icmp_seq=6 ttl=64 time=0.026 ms 64 bytes from 10.1.4.13: icmp_seq=7 ttl=64 time=0.024 ms 64 bytes from 10.1.4.13: icmp_seq=8 ttl=64 time=0.023 ms 64 bytes from 10.1.4.13: icmp_seq=9 ttl=64 time=0.033 ms 64 bytes from 10.1.4.13: icmp_seq=10 ttl=64 time=0.021 ms ^C --- 10.1.4.13 ping statistics --- 10 packets transmitted, 10 received, 0% packet loss, time 9001ms rtt min/avg/max/mdev = 0.020/0.027/0.047/0.007 ms

Am 21.05.24 um 15:08 schrieb Anthony D'Atri:

...

Check the netmask on your interfaces, is it possible that you're sending inter-node traffic up and back down needlessly?

...

On May 21, 2024, at 06:02, Stefan Bauer<sb@plzk.de> wrote:

Dear Users,

i recently setup a new ceph 3 node cluster. Network is meshed between all nodes (2 x 25G with DAC). Storage is flash only (Kioxia 3.2 TBBiCS FLASH 3D TLC, KCMYXVUG3T20)

The latency with ping tests between the nodes shows:

# ping 10.1.3.13 PING 10.1.3.13 (10.1.3.13) 56(84) bytes of data. 64 bytes from 10.1.3.13: icmp_seq=1 ttl=64 time=0.145 ms 64 bytes from 10.1.3.13: icmp_seq=2 ttl=64 time=0.180 ms 64 bytes from 10.1.3.13: icmp_seq=3 ttl=64 time=0.180 ms 64 bytes from 10.1.3.13: icmp_seq=4 ttl=64 time=0.115 ms 64 bytes from 10.1.3.13: icmp_seq=5 ttl=64 time=0.110 ms 64 bytes from 10.1.3.13: icmp_seq=6 ttl=64 time=0.120 ms 64 bytes from 10.1.3.13: icmp_seq=7 ttl=64 time=0.124 ms 64 bytes from 10.1.3.13: icmp_seq=8 ttl=64 time=0.140 ms 64 bytes from 10.1.3.13: icmp_seq=9 ttl=64 time=0.127 ms 64 bytes from 10.1.3.13: icmp_seq=10 ttl=64 time=0.143 ms 64 bytes from 10.1.3.13: icmp_seq=11 ttl=64 time=0.129 ms --- 10.1.3.13 ping statistics --- 11 packets transmitted, 11 received, 0% packet loss, time 10242ms rtt min/avg/max/mdev = 0.110/0.137/0.180/0.022 ms

On another cluster i have much better values, with 10G SFP+ and fibre-cables:

64 bytes from large-ipv6-ip: icmp_seq=42 ttl=64 time=0.081 ms 64 bytes from large-ipv6-ip: icmp_seq=43 ttl=64 time=0.078 ms 64 bytes from large-ipv6-ip: icmp_seq=44 ttl=64 time=0.084 ms 64 bytes from large-ipv6-ip: icmp_seq=45 ttl=64 time=0.075 ms 64 bytes from large-ipv6-ip: icmp_seq=46 ttl=64 time=0.071 ms 64 bytes from large-ipv6-ip: icmp_seq=47 ttl=64 time=0.081 ms 64 bytes from large-ipv6-ip: icmp_seq=48 ttl=64 time=0.074 ms 64 bytes from large-ipv6-ip: icmp_seq=49 ttl=64 time=0.085 ms 64 bytes from large-ipv6-ip: icmp_seq=50 ttl=64 time=0.077 ms 64 bytes from large-ipv6-ip: icmp_seq=51 ttl=64 time=0.080 ms 64 bytes from large-ipv6-ip: icmp_seq=52 ttl=64 time=0.084 ms 64 bytes from large-ipv6-ip: icmp_seq=53 ttl=64 time=0.084 ms ^C --- long-ipv6-ip ping statistics --- 53 packets transmitted, 53 received, 0% packet loss, time 53260ms rtt min/avg/max/mdev = 0.071/0.082/0.111/0.006 ms

If i want best performance, does the latency difference matter at all? Should i change DAC to SFP-transceivers wwith fibre-cables to improve overall ceph performance or is this nitpicking?

Thanks a lot.

Stefan _______________________________________________ ceph-users mailing list --ceph-users@ceph.io To unsubscribe send an email toceph-users-leave@ceph.io -- Mit freundlichen Grüßen

Stefan Bauer Schulstraße 5 83308 Trostberg 0179-1194767 _______________________________________________ ceph-users mailing list --ceph-users@ceph.io To unsubscribe send an email toceph-users-leave@ceph.io

-- Mit freundlichen Grüßen Stefan Bauer Schulstraße 5 83308 Trostberg 0179-1194767 _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-leave@ceph.io