Ceph - Which is faster/preferred?

[Neo42TheOne]

I am in the process of ordering new servers for our company to set up a 5-node cluster with all NVME.
I have a choice of either going with (4) 15.3TB drives or (8) 7.68TB drives.
The cost is about the same.
Are there any advantages/disadvantages in relation to Proxmox/Ceph performance?
I think I remember reading something a while back about the more OSD's the better, but it did not say how many is "more".

 

[alexskysilk]

Are there any advantages/disadvantages in relation to Proxmox/Ceph performance?

Larger NVMEs tend to perform better, BUT ceph performance increases more linearly with more OSDs. It would probably wash if you create twice as many OSDs on the larger drives (one faster disk vs 2 slower ones,) but the disk failure domain would be a multiple of OSDs.

 

[SteveITS]

If one 15 TB disk fails it will need to rebalance all of that disk's data to other drives. More disks = more I/O paths.

 

[ness1602]

I have these disks(SSDPE2NV153T8) in one of the cluster i'm maitaining. They are okay. But i would always stick more disks than bigger disks.