Clarification on Ceph OSD Memory Recommendation

ryantw

New Member
Jul 24, 2024
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Hi all,

I'm wondering about this recommendation for memory requirements for Ceph from the Proxmox VE admin guide: "1 TiB of data, 1 GiB of memory"

I've not seen this elsewhere. Ceph's offical docs have a recommendation of 4 GiB per OSD, though are clear that OSDs can benefit from more memory.

I'm trying to understand where the 1 GiB per 1 TiB recommendation fits:
  • It sounds like this is in addition to the per-OSD memory requirement? 4 GiB + 1 GiB per TiB for every OSD?
  • If I have ten 10 TiB drives, for a total of ten OSDs and 100 TiB storage, would I really need to dedicate 140 GiB of memory to OSDs?
  • Does this recommendation mean that the osd_memory_target parameter should be adjusted, or is this memory anticipated to be used in some other way?
  • Is this recommendation due to the co-location of Proxmox and VMs on the same hardware as Ceph in any way?
Thanks in advance.
 
Did you ever figure this out?