Ceph: Control which server has which data

[coder]

Hello All,

Is there a possibility to control where Ceph puts data from specific VMs on?

I mean, when I have a 6 six cluster with a replica setting of 3:2. Is it then possible to decide which of the 6 nodes might be used.

For example:

Nodes: A B C D E F

I want to have Ceph makes use of the nodes D E F only for dedicated VM.

Maybe through a modification of the CRUSH map?

Thanks,
Volker

 

[alexskysilk]

Possible- yes. you can create server group classes and use them as your source for the pools crush rule (and before you ask- https://docs.ceph.com/en/latest/rados/operations/crush-map/)

But.... why?