Lots of opinions in this arena. Below are mine. ymmv. >> 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> A bit dated, note the reference to Jewel and thus XFS / Filestore. >> Redmine >> tracker.ceph.com >> Is there anybody have some good how to on this topic? Wido's presentation from a few years ago re affordable NVMe Ceph may be of interest. > I'm also interested in how to configure NUMA for Ceph. My sense is that with recent OS and kernel releases (e.g., not CentOS 8) irqbalance does a halfway decent job. > 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. My sense is that NUMA is very much a function of what CPUs one is using, and 1S vs 2S / 4S. With 4S servers I've seen people using multiple NICs, multiple HBAs, etc., effectively partitioning into 4x 1S servers. Why not save yourself hassle and just use 1S to begin with? 4+S-capable CPUs cost more and sometimes lag generationally. cf. Mark and Dan's Journey to 1TB/s post, it discusses the impact of inter-socket communication and IOMMU. With EPYCs, one may gain by disabling IOMMU on the kernel commandline, and other tunings including NPS values. Xeons may require less adjustment from defaults. There is growing favor for 1S servers. 2S has been de-facto for years, because CPUs with higher core counts were disproportionally expensive. XCC vs MCC CPU SKUs may matter too. With Emerald Rapids and Genoa, we may be able to afford a desired core/thread count (say, 4-6 vcores/threads per NVMe OSD) with a single socket. Note that 1S servers may have differing RAM population dynamics. > > Red Hat documentation (hyper converged infra) I may be heterodox, but I dislike convergence. ymmv. > 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. Look up your server / motherboard specifically. With, say, Dell systems, there are often multiple variants of a model, each with very different PCI-e - NVMe mappings. Especially if there is an antiquated and counterproductive RAID HBA present, the NVMe bays may not be even close to evenly distributed across two sockets. > 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)? That sounds like two servers to me. One reason I favor 1S 1U servers for Ceph. > > 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)). cf. the NPS setting in BIOS. > 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 >> ________________________________ >> This message is confidential and is for the sole use of the intended recipient(s). It may also be privileged or otherwise protected by copyright or other legal rules. If you have received it by mistake please let us know by reply email and delete it from your system. It is prohibited to copy this message or disclose its content to anyone. 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