> Not with the most recent Ceph releases. Actually, this depends. If its SSDs for which IOPs profit from higher iodepth, it is very likely to improve performance, because until today each OSD has only one kv_sync_thread and this is typically the bottleneck with heavy IOPs load. Having 2-4 kv_sync_threads per SSD, meaning 2-4 OSDs per disk, will help a lot if this thread is saturating.
For NVMes this is usually not required. The question still remains, do you have enough CPU? If you have 13 disks with 4 OSDs each, you will need a core-count of at least 50-ish per host. Newer OSDs might be able to utilize even more on fast disks. You will also need 4 times the RAM. > I suspect your PGs are too few though. In addition, on these drives you should aim for 150-200 PGs per OSD (another reason to go x4 OSDs - x4 PGs per drive). We have 198PGs/OSD on average and this helps a lot with IO, recovery, everything. Best regards, ================= Frank Schilder AIT Risø Campus Bygning 109, rum S14 ________________________________________ From: Anthony D'Atri <[email protected]> Sent: Tuesday, May 21, 2024 3:06 PM To: 서민우 Cc: Frank Schilder; [email protected] Subject: Re: [ceph-users] Please discuss about Slow Peering I have additional questions, We use 13 disk (3.2TB NVMe) per server and allocate one OSD to each disk. In other words 1 Node has 13 osds. Do you think this is inefficient? Is it better to create more OSD by creating LV on the disk? Not with the most recent Ceph releases. I suspect your PGs are too few though. _______________________________________________ ceph-users mailing list -- [email protected] To unsubscribe send an email to [email protected]
