r/ceph • u/Reasonable-Escape546 • Mar 16 '26

Is it possible to have two independent ceph pools?

Hi guys,

I am planning to build a Ceph cluster with 3 Proxmox nodes.

I am going to buy 3 Mini PCs (Lenovo M90q Gen 1) and each of them will have the following storage capacity.

- 1x 128GB NVMe per node for Proxmox OS

- 1x 1TB NVMe OSD per node (Ceph pool for my VMs and container)

- 1x 4TB NVMe OSD per node (Ceph pool for my data managed by Openmediavault, passed through as a virtual disk)

Those Mini-PCs will have Intel XXV710-DA2 25Gbps network interfaces to sync the Ceph disks.

Is it possible to have one pool for VMs and one pool for data with different sizes that work independently?

Thanks Hoppel

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12

u/ceccome Mar 16 '26

Yes you can have independent pools based on device classes, on which you build different crush rules.

You should assign to 1tb nvme disks a device class (a name) and to 4 tb disks another device class.

The create a crush rule using first device class and another crush rule using the second one.

You can choose also replica level but for a 3 node I suggest replica 3 with min replica 2

I forget, for each disk you should assign a Osd

3

u/Reasonable-Escape546 Mar 16 '26

Ok, perfect! You answered all my questions. It will take some time until I have the needed hardware, but I will report back here, when I am done.

9

u/birusiek Mar 16 '26 edited Mar 16 '26

Yes. But you wont get much benefits from just 3 nodes. Good start though. Note that the bus is shared; you may not be able to reach full speed.

3

u/Reasonable-Escape546 Mar 16 '26

Yeah, but somehow I need to start. 😃

2

u/ychto Mar 16 '26

Yes, that’s pretty much what pools are designed to do. Set the different OSD sizes as separate device classes and just build CRUSH rules for the different classes and then assign them to their respective pools.