If you choose to join an existing Virtuozzo Storage cluster, you will need to provide the cluster name and password and select one or more roles for your server.
First, in the Name field, specify a name of the cluster to join.
Next, click Configure security next to the Name field and specify a password for your cluster.
Next, choose the cluster role(s) for your server. Each server can have one, some, or all of the following roles.
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Metadata Server Role. MDS servers are an essential part of any Virtuozzo 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.
As a static IP address is required for an MDS server, the IP address detected by the installation program is specified in the corresponding field by default. If multiple IP addresses are available, you need to to choose one to assign to the MDS server. In some cases, you may need to enter a valid IP address manually.
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Note: MDS servers require static IP addresses. If you are using DHCP, map an IP address to the MAC address of the MDS server.
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Chunk Server Role. Chunk servers (CS) 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 for high data availability. If one of the chunk servers goes down, other chunk servers continue providing the replicas of data chunks that were stored on the failed server.
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Warning: Virtuozzo Storage has redundancy built in, so you should avoid running Virtuozzo 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 Virtuozzo 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 Virtuozzo 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 except system to act as a separate chunk server.
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If one or more SSD drives are available on the server, they will be set up to store chunk server write journals (one journal per chunk server). By using SSD drives for write journaling, you can boost the performance of write operations in the cluster by up to two or more times. For more information on using SSD drives, consult the Virtuozzo Storage Administrator’s Guide. If you need to disable this setting, click Configure under the chunk server role checkbox and clear the checkbox Enable the use of SSD drives for the CS journal.
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Note: If one or more SSDs are not detected automatically, find out their device names (for example, invoke the console by pressing Ctrl+Alt+F2 and run
lsblk -d -o name,rota, zeroes in the ROTA column will indicate non-rotational drives, i.e. SSDs), reboot to the installer welcome screen, and follow instructions in Section 2.1.2, “Enabling Forced Detection of SSDs”.
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Client Server Role. Clients are computers with Virtuozzo 7 from where you run virtual machines and containers stored in your Virtuozzo Storage cluster.
By default, the installer does the following:
- Enables high availability support for the client and for all virtual machines and containers you will create on it. With high availability enabled, 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 Virtuozzo 7 User’s Guide.
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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 Virtuozzo Storage Administrator’s Guide.
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Note: If one or more SSDs are not detected automatically, find out their drive letters (for example, invoke the console by pressing Ctrl+Alt+F2 and run
lsblk -d -o name,rota, zeroes in the ROTA column will indicate non-rotational drives, i.e. SSDs), reboot to the installer welcome screen, and follow instructions in Section 2.1.2, “Enabling Forced Detection of SSDs”.
To change either of these settings, click Configure under the client role checkbox and set the corresponding checkboxes in the client settings window.
