On 07-05-2024 22:37, Szabo, Istvan (Agoda) wrote:
Hi,
Haven't really found a proper descripton in case of 2 socket how to pin osds to numa node, only this: https://tracker.ceph.com/projects/ceph/wiki/Tuning_for_All_Flash_Deployments#Ceph-Storage-Node-NUMA-Tuning
Tuning for All Flash Deployments - Ceph - Ceph <https://tracker.ceph.com/projects/ceph/wiki/Tuning_for_All_Flash_Deployments#Ceph-Storage-Node-NUMA-Tuning>
Redmine
tracker.ceph.com
Is there anybody have some good how to on this topic?
I'm also interested in how to configure NUMA for Ceph. I came across a
recent Ceph day NYC talk from Tyler Stachecki (Bloomberg) [1] and a
Reddit post [2]. Apparently there is quita a bit of performance to gain
when NUMA is optimally configured for Ceph. But what is an optimal
configuration is not clearly explained (for me at least). So I'm looking
for more information on this topic.
Red Hat documentation (hyper converged infra) suggests to pin the Ceph
processes on the CPU with the storage controller / NIC attached [3]. In
an all flash system there is not just one storage controller but the
NVMe are attached to different PCIe buses spread across the different
NUMA nodes. So what is most optimal there? Does it still make sense to
have the Ceph processes bound to the CPU where their respective NVMe
resides when the network interface card is attached to another CPU /
NUMA node? Or would this just result in more inter NUMA traffic
(latency) and negate any possible gains that could have been made?
Is the benefit of NUMA optimization so large that it would make sense to
add another NIC to the system, add it to the other NUMA domain and have
half the OSDs listen on one nic (IP), and the rest of the OSDs on the
other nic (separate IP)?
Ceph has an admin command to show the NUMA status that gives the
following output for a node called storage1:
ceph osd numa-status
OSD HOST NETWORK STORAGE AFFINITY CPUS
0 storage1 - 2 - -
1 storage1 - 2 - -
2 storage1 - 2 - -
3 storage1 - 1 - -
4 storage1 - 1 - -
5 storage1 - 0 - -
6 storage1 - 0 - -
7 storage1 - 0 - -
8 storage1 - 2 - -
But I'm unsure what that means. Because when I look up the numa status
for the OSD processes it shows the following:
numactl -s 22579
policy: default
preferred node: current
physcpubind: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
23 24 25 26 27 28 29 30 31
cpubind: 1 2
nodebind: 1 2
membind: 1 2
And its the same for all OSDs (NUMA node 0 / 4 only have CPUs and no
memory (AMD EPYC 7343 16-Core Processor)). So the default policy seems
to be active, and no Ceph NUMA affinity seems to have taken place. Can
someone explain me what Ceph (cephadm) is currently doing when the
"osd_numa_auto_affinity" config setting is true and NUMA is exposed?
Thanks in advance for any NUMA clue you can give me.
Gr. Stefan
[1]: https://www.youtube.com/watch?v=u8vgo2jfMpo
[2]:
https://www.reddit.com/r/ceph/comments/15b3rp8/clyso_enterprise_storage_allflash_ceph_deployment/
[3]:
https://docs.redhat.com/en/documentation/red_hat_openstack_platform/11/html/hyper-converged_infrastructure_guide/resource-isolation#resource-isolation-numa
Thank you
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