Erasure-encoded Pools

In this article, we will take a look at erasure-encoded pools. So far, most pools that we used are replicated pools.

Overview

According to the Ceph documentation, this kind of pools enables storage size requirement to be fine-tuned, generally requiring less storage space, with limited functionality. It also uses more computational resource.

Due to the limited supported operations, it seems to have limited usage cases, mainly for object storage. In this series of articles, we have seen erasure-encoded pools only once. It is a pool associated to the object storage in the deployment using Rook on a Kubernetes cluster. However, we have not looked into it in detail.

Erasure-encoded pool deployed in Kubernetes by Rook

Before we explain how to create erasure-encoded pools, let’s take a look at the pool in the deployment by Rook operator.

To access the ceph cluster in the Kubernetes, we need to access a toolbox pod. This is how to find one and connect to it.

kubectl -n rook-ceph get pods -l "app=rook-ceph-tools"
kubectl -n rook-ceph exec -it rook-ceph-tools-877d765f-pt7h5 -- /bin/bash

The first command will display the toolbox pod name. The pod name changed from the previous article since the Kubernetes cluster was brought down and it is restarted for this article.