setting up the ceph cluster

proxmox-ceph.md

CEPH HA Setup

Note this should only be done once you are sure you have reliable TB mesh network.

this is because proxmox UI seems fragile wrt to changing underlying network after configuration of ceph.

All installation done via command line due to gui not understanding the mesh network

This setup doesn't attempt to seperate the ceph public network and ceph cluster network (not same as proxmox clutser network), The goal is to get an easy working setup.

this gist is part of this series

Ceph Initial Install & monitor creation

1. On all nodes execute the command pveceph install --repository no-subscription accept all the packages and install
2. On node 1 execute the command pveceph init --network 10.0.0.81/24
3. On node 1 execute the command pveceph mon create --mon-address 10.0.0.81
4. On node 2 execute the command pveceph mon create --mon-address 10.0.0.82
5. On node 3 execute the command pveceph mon create --mon-address 10.0.0.83

Now if you access the gui Datacenter > pve1 > ceph > monitor you should have 3 running monitors (ignore any errors on the root ceph UI leaf for now).

If so you can proceed to next step. If not you probably have something wrong in your network, check all settings.

Add Addtional managers

1. On any node go to Datacenter > nodename > ceph > monitor and click create manager in the manager section.
2. Selecty an node that doesn't have a manager from the drop dwon and click create 3 repeat step 2 as needed If this fails it probably means your networking is not working

Add OSDs

1. On any node go to Datacenter > nodename > ceph > OSD
2. click create OSDselect all the defaults (again this for a simple setup)
3. repeat untill you have 3 nodes like this (note it can take 30 seconds for a new OSD to go green)

If you find there are no availale disks when you try to add it probably means your dedicated nvme/ssd has some other filesystem or old osd on it. To wipe the disk use the following UI. Becareful not to wipe your OS disk.

Create Pool

1. On any node go to Datacenter > nodename > ceph > pools and click create
2. name the volume, e.g. vm-disks and leave defaults as is and click create

Configure HA

1. On any node go to Datacenter > options
2. Set Cluster Resource Scheduling to ha-rebalance-on-start=1 (this will rebalance nodes as needed)
3. Set HA Settings to shutdown_policy=migrate (this will migrate VMs and CTs if you gracefully shutdown a node).
4. Set migration settings leave as default (seperate gist will talk about seperating migration network later)

ok, i've been playing around with various mtu sizes, there's no perceivable difference on my hardware in iperf3 speeds for an mtu betweeen 1500 and 34,000. I always wind up with an iperf3 test of around 22-23gbps. Going to 35,000 i get lockups with ceph.

Using the ceph benchmark tool rados, on a write test, is a good way to stress test and see if i will get a lockup without having to use real world load. Additionally, i consistently get the best write throughput and iop performance with an mtu of 1500 with my current hardware. I am using consumer wd sn850x m.2 drives, until i get some enterprise ones, so this could have an impact on this as well.

I have some Samsung PM9A3 u.2 drives on the way, along with some PM983 m.2 drives. Once i get those i'll do another round of testing and hopefully put this stack into production to replace my r730.