Setting Up Chunk Servers

A chunk server stores actual data of virtual machines and Containers and services requests to it. All data is split into chunks and can be stored in a Parallels Cloud Storage cluster in multiple copies called replicas .

Initially, any cluster is configured to have only one replica per each data chunk, which is sufficient to evaluate the Parallels Cloud Storage functionality using one server only. In production, however, to provide high availability for your data, you need to configure the cluster for each data chunk to have at least three replicas. This requires at least three chunk servers to be set up in the cluster. You can modify the default replication parameter using the pstorage utility. For details, see Configuring Replication Parameters .

Notes:

1. Using shared JBOD arrays across multiple nodes running CS services may introduce a single point of failure and make the cluster unavailable if all data replicas happen to be allocated and stored on the failed JBOD. For more information, see Configuring Failure Domains .

2. Do not place chunk servers on disks already used in other I/O workloads, e.g., system or swap. Sharing disks between CS and other sources of I/O will result in severe performance loss and high I/O latencies.

The process of setting up a chunk server includes two stages:

1. Preparing to create a chunk server .
2. Creating the chunk server .

Note: You can configure hot plugging so that a chunk server is created automatically when you attach an HDD to the server. For more information, see the pstorage-hotplugd man page.