Joining an Existing Parallels Cloud Storage Cluster

If you select the Join an existing Parallels Cloud Storage option and click Next , you will see this window:

Specify the parameters to join your new server to the cluster:

1. Cluster name : Specify the name of the Parallels Cloud Storage you want to join your server to.

   In most cases, the installer automatically detects all Parallels Cloud Storage clusters in your network and displays their names as a list box to the right of the Cluster name field. If the installer cannot find any cluster, it shows a warning, and you need to manually type the cluster name in the provided field.

2. Security settings . Click the button and specify the password to authenticate your new server in the cluster. Type the password you specified when creating the cluster and press Enter.
3. Metadata Server Role . Specify whether the installer should configure your server to act as a metadata (MDS) server in the cluster. MDS servers are an essential part of any Parallels Cloud Storage cluster. They store metadata about chunk servers and control how files keeping the contents of virtual machines and Containers are split into chunks and where these chunks are located.

   When you create a new Parallels Cloud Storage cluster, the Metadata Server Role option is selected by default. To set up an MDS server, you need to specify an IP address to use for connecting to this server. You can type it manually in the IP address field or click the arrow at the end of the field and choose one from the list of IP addresses that were detected by the installer (it shows all IP addresses it could find for the server).

   Note: MDS servers must have static IP addresses assigned. If you are using DHCP, map an IP address to the MAC address of the MDS server.

4. Chunk Server Role . Specify whether the installer should configure your server to act as a chunk server in the cluster. Chunk servers store the contents of virtual machines and Containers in the form of fixed-size chunks and provide access to these chunks. All data chunks are replicated and the replicas are kept on different chunk servers to achieve high availability. If one of the chunk servers goes down, the other chunk servers will continue providing the data chunks that were stored on the failed server.

   Warning: Parallels Cloud Storage has redundancy built in, so you should avoid running Parallels Cloud Storage on redundant types of RAID like 1, 5, or 6 over local storage. In this case, a single write operation may affect a significant number of HDDs resulting in very poor performance. For example, for 3 Parallels Cloud Storage replicas and RAID5 on servers with 5 HDDs each, a single write operation may result in 15 I/O operations. For recommendations on optimal local storage configurations, consult the Parallels Cloud Storage Administrator's Guide .

   By default, the installer does the following:

   • If your server has several disk drives, the installer will automatically configure each disk drive to act as a separate chunk server.
   • If one or more SSD drives are available on the server, they will be set up to store chunk server write journals (each chunk server will get its own journal). By using SSD drives for write journaling, you can boost the performance of write operations in the cluster by up to 2 and more times. For more information on using SSD drives, consult the Parallels Cloud Storage Administrator's Guide .

     Note: If one or more SSDs are not detected automatically, find out their drive letters (e.g., invoke the console by pressing Ctrl+Alt+F2 and analyze dmesg output), reboot to the installer Welcome screen, and see Enabling Forced Detection of SSDs for instructions.

   To check the chunk server settings that will be applied to your disk drives, click the Chunk Server settings button.

5. Client Server Role : Specify whether the installer should configure your server to act as a client in the cluster. Clients are computers with Parallels Cloud Server 6.0 from where you run virtual machines and Containers stored in your Parallels Cloud Storage cluster.

   By default, the installer

   • Enables High Availability support for the client and for all virtual machines and Containers you will create on it. With High Availability turned on, if the client fails, all virtual machines and Containers hosted on it will be automatically moved to a healthy server. For detailed information on High Availability, consult the Parallels Cloud Server 6.0 User's Guide .
   • If one or more SSD drives are available on the server, configures them to store a local cache of frequently accessed data. By having a local cache on an SSD drive, you can increase the overall cluster performance by up to 10 and more times. For more information on using SSD drives, consult the Parallels Cloud Storage Administrator's Guide .

     Note: If one or more SSDs are not detected automatically, find out their drive letters (e.g., invoke the console by pressing Ctrl+Alt+F2 and analyze dmesg output), reboot to the installer Welcome screen, and see Enabling Forced Detection of SSDs for instructions.

   Using the Client settings button, you can check whether the support for using SSD drives to store a local cache is enabled.

When you are done, click Next .