[PVE-User] Create proxmox cluster / storage question.

Ronny Aasen ronny+pve-user at aasen.cx
Mon Mar 2 09:20:53 CET 2020

On 28.02.2020 15:25, Leandro Roggerone wrote:
> Dear Eneko:
> When you talk about redundacy and availability, do you want...
> - HA? (automatic restart of VMs in the other node in case one server fails)
> - Be able to move VMs from one server to the other "fast" (without
> copying the disks)?
> Yes , this is what I want.
> So regarding my original layout from my 5.5Tb  storage:
> Im using 1T for LVM , 1TB for LVM-thin and  3.5 TB unassigned space, is it
> ok to use this unassigned space for a ceph ?
> Can I set it later ?  with server on production ?
> Other:
> Using an NFS system, means to have an external server running a file sistem?
> So you should have at least two servers for the cluster and one for the
> file system?
> It seems to me that using ceph has a better redundancy plan an it is easier
> to deploy since I only need two servers. (am i right?).
> Thanks!
> El vie., 28 feb. 2020 a las 11:06, Eneko Lacunza (<elacunza at binovo.es>)
> escribió:
>> Hola Leandro,

for NFS you have just moved your SPOF from proxmox to NFS. so unless you 
have a HA NFS solution like a SAN with controller failover i would not 
think about NFS.

for ceph you need 4 server to a have a proper fault tolerant HA system
you have 3 copies of data. and a node as a failuredomain. you want the 
disk layout to be fairly identical on the servers.

you can in theory run ceph on 3 nodes, but you will have a degraded 
cluster when you loose a node. and basically neuter the best features of 
ceph. so use 4 or more nodes. ceph really shines when you get to 8-10 
nodes. also most defaults assume a 8 node cluster, so you may need to 
tweak some warning levels when you want to run with fewer.

Also proxmox HA requires quorum. so proxmox also need 3 or more nodes. 
if you only have 2 nodes you can not do a reliable HA solution. But you 
can do a zfs replication system, where the running vm is replicated to 
the other server periodically. and you can start that backup vm when the 
main one dies.

Good luck
Ronny Aasen

More information about the pve-user mailing list