[sheepdog-users] Multiple storage clusters per node

[Liu Yuan]

On Tue, Mar 04, 2014 at 04:35:15PM +0100, Walid Moghrabi wrote:
> Hi everyone, 
> 
> 
> I'm definitely found of Sheepdog, this is great and this is exactly what I need and it works extremely well with ProxMox. 
> I experimented a lot with a ProxMox cluster running Sheepdog 0.8 and qemu 1.7 in our lab and it is really impressive. 
> 

Welcome to become a sheepdog walker :)

> 
> Now, we would like to deploy this solution to replace our beta environment on a brand new 3 nodes ProxMox cluster running on dedicated servers at OVH (a french hosting company). 
> 
> 
> These nodes are identical and using this local storage layout : 
> 
> 
> Hardware RAID with LSI Logic MegaRAID controler with 1GB BBU onboard memory. 
> On this controler are defines 2 RAID volumes : 
> * one RAID1 volume with 2x3TB SATA III mechanical hard drives 
> * one RAID0 volume with 2x300GB SATA III Intel S3500 SSD drives 
> 
> 
> Our will is to create 2 Sheepdog storage clusters on these nodes : 
> * one "small but fast" using only SSD drives 
> * one "big but slow" using only mechanical SATA drives 
> 
> 
> We don't want to mix storage types to make on big sheepdog storage, we really want separated servers. 
> 
> 
> I tried different settings but I can't do that, I always end with one mixed storage even if I run 2 different sheepdog servers binded on different ports or IPs and using different rootdirs, pids, ... 
> 
> 
> Whatever I try, I'm stuck with one volume only. 
> 
> 
> So here are my questions : 
> 
> 
> * Is it possible to have multiple storage instances per nodes ? 
> * If so, how ? 

Sure. In sheepdog, one daemon actually represent a node. You can run however
much daemons per host.


> For now I'm stuck and I really don't know where to go now :( 
> 

It depends on corosync or zookeeper, which act as a membership manamgent software
for sheepdog.

For corosync, you have 1:1 map of corosync to sheep daemon. So you have to setup
2 corosync for two cluster on each node.

For zookeeper, one zk cluster manages a sheepdog cluster. So you have to setup
2 zk clusters to manage different sheepdog clusters.

For stability, we recommend zookeeper, which proves to be more realiable for long
running sheepdog cluster.

Thanks
Yuan