need help with creating ceph storage

[halnabriss]

I am making a cluster among three PVE servers, the 1st server has ( 8 x 1TB disks) , the 2nd and the 3rd servers have ( 24 x 1.2 TB disks )

I finished all the required configurations for clustering and ceph, but I dont know what is the optimal configuration for my pool to be able to survive the failure of one node.

I think that using three replicas here will make many problems because one of the servers has only 8 TB storage while the others have almost 30 TB .

so, What is the max/min configurations ??

thanks in advance

 

[tschanness]

I finished all the required configurations for clustering and ceph, but I dont know what is the optimal configuration for my pool to be able to survive the failure of one node.

I think that using three replicas here will make many problems because one of the servers has only 8 TB storage while the others have almost 30 TB .

With three nodes? Well, you'll have only 8TB usable storage or you won't have a redundant storage.

 

[halnabriss]

what if I configure the pool to make only 2 replicas (max =2 ) and min =2 , what the problems with this pool ? and what if I make max = 2 and min =1 ??

 

[halnabriss]

I configured my pool to have 2 replicas (max=2) and min =1 , what are the dangers of this configuration?
any help please ??

 

[Alwin]

In small clusters, the size 2 / min_size 1 holds the risk that in a degraded state the remaining objects might get lost too. As the recovery may move a object from one OSD to the next.
http://docs.ceph.com/docs/luminous/rados/operations/pools/#set-the-number-of-object-replicas