On Tuesday, December 16, 2025 at 08:21:43 a.m. EST, Anthony D'Atri via ceph-users <ceph-users@ceph.io> wrote:

If up-front CapEx is your concern, remember that you don't have to fully populate nodes with drives, at least not initially.  I sometimes recommend a minimum of 7 nodes so that 4+2 or 3+3 EC can be done safely. Seven nodes half-full is better in multiple ways than 4 nodes  fully populated.

As for nodes, used Dell R640 can be had with 8 or 10 NVMe bays and lots of cores very inexpensively these days. Will they give another (let's be honest) 10 years of service?  Hard to say. But today's SSDs can be transplanted into tomorrow's chassis, and when the latter is cheap, one can easily afford to lay in a couple of spares.  It's like with full-frame digital photography: a body from 10 years ago is meh by today's standards, but that $10,000 lens for shooting sports ball is still golden.

We're in a situation where we've got nodes that we can use, so it's mostly about the drive cost and configuration. The nodes are in chassis of 4 nodes each. Would there be any problem with putting a 4+2 or 3+3 config into 8 nodes? And any problem with having 7 monitors running on Proxmox nodes that are part of the Ceph cluster but aren't running any OSDs? (Obviously we wouldn't be able to survive the loss of a chassis in this config.) Andrew