In this topic:
A server group can consist of up to 64 DataCore Servers.
Servers in the same group will exchange configuration information and most operations can be performed from all servers in the group.
- When adding a DataCore server to a server group, make sure that it is not registered as a host in a server group that it is being added to. Otherwise, the iSCSI initiator will not be displayed in the DataCore Management Console.
- When connecting to a server which is part of a group, the user credentials will be authenticated on each server in the group. Therefore, the same user accounts and passwords (domain or local) must exist on all DataCore Servers in the same server group. If using the local Administrator account, that password must also match on all servers in the group. See Connecting to a Server Group for more important information.
- The DcsAdmin password, entered during software installation, for the server being added must be identical to the DcsAdmin password being used by all existing DataCore Servers in the server group.
- DataCore Servers (including Replication partners) and remote DataCore Management Consoles require functioning name resolution to resolve computer names to IP addresses. To ensure proper communication and data transfer, each server running DataCore SANsymphony must be able to resolve the host names of each DataCore Server in the server group to which it belongs. If using hosts files, the name in the file must be identical to the actual computer name, including the case. See Name Resolution for important information.
- DataCore highly recommends using host names instead of IP addresses. IP addresses can be determined from host names regardless of changes to the IP addresses.
A server with existing virtual disks or virtual disk templates cannot be added to an existing server group. When a server with an existing configuration is added to a server group, some configuration of the server being added will be deleted, such as hosts, users, ports, tasks and so on.
- When adding a new server to an existing group, always invoke the Add DataCore Server operation from the existing group.
(After the new server is added to the group, then activate the license keys for the new server.)
- Servers being added to a server group should be running the same version of DataCore SANsymphony as the existing server group. Running different versions of software on servers in the same server group are not supported. If necessary, upgrade software on servers as appropriate before adding new servers to the group.
- The server being added to the group will have virtualization started automatically.
- The Auto-login iSCSI ports check box on the Add DataCore Server dialog box (used to add a server to an existing server group) enables or disables the automatic login of all iSCSI ports between the server being added and all existing servers in the server group.
- By default auto-login is disabled. Auto-login between all iSCSI ports in large server groups can take a considerable amount of time to complete and may cause a lag in response in the user interface. For best performance in Server Groups with a large number of servers, check the Disable iSCSI auto-login check box
- Auto-login should be disabled in order to selectively login iSCSI ports between servers.
- When auto-login is disabled, iSCSI ports must be performed manually on the iSCSI Initiator Details page. See Configuring iSCSI Connections for more information.
- The connection interface is used to connect to a server group and establishes a TCP session for each DataCore Server. This interface is used for communication between DataCore Servers, replication partnerships, and DataCore Management Consoles. See the Assigning a Server Group Connection Interface section below.
To add a server to the local server group:
- In the DataCore Servers panel, right-click the server group at the top of the panel and select Add DataCore Server from the context menu.
Alternatively, you can add a server from:
- The Getting Started page by clicking on the Add a DataCore Server link.
- The Ribbon>Common Actions tab by clicking Add DataCore Server.
- In the Add DataCore Server dialog box, enter the name or IP address of the server to add.
Name or IP address will be used to connect to the server group and for communications between DataCore Servers. Also see Assigning a Server Group Connection Interface for more information.
- The Auto-login iSCSI ports check box enables or disables automatic login of all iSCSI ports between the new server being added and the existing servers in the server group. Ensure that the check box is selected or cleared as desired.
- Click Add to continue. A message will appear in the dialog box that reads Adding server, please wait... while the server is being added. The box closes when the server has been added.
- If the server that was added has existing pools which are marked as foreign, then import the pools.
(Foreign pools will have a warning icon in the DataCore Servers panel.)
- If using the replication feature, rename the server group.
After the server is added:
- A DataCore Server Details page is also created for the new server.
A DataCore Server can be removed from the local server group if necessary. Removing the server places the server in its own individual server group.
Before a DataCore Server is removed from a server group, the storage sources created from the server to be removed must be split from all multi-copy virtual disks or deleted. A multi-copy virtual disk is comprised of two or more data copies; each copy from a different server. Also, if the server is removed and then virtual disks are created on the server, that server cannot be added back to the original server group unless those virtual disks are deleted first.
To remove a DataCore Server from the local server group:
- In the DataCore Servers panel, right-click the server that you want to remove and choose Remove DataCore Server.
- A confirmation message will appear, read the warning. Select the check box and click Yes to continue with the operation.
- After the server is removed, it will retain the same server group name. Rename the server group if desired.
The connection interface is used to connect to a server group and establishes a TCP session. This interface is used for inter-node communication between DataCore Servers, replication partnerships, and DataCore Management Consoles. See Name Resolution for important information.
The connection interface can be assigned for each DataCore Server. The default setting is All. In this case, the connection is made using the host name and the IP address is resolved by the name service.
A specific IP address can also be assigned for the connection interface.
- Setting a specific IP address for the connection interface will override name resolution provided by the name service. Before assigning or changing the connection interface, consider any Hosts files that are configured on the DataCore Server and any Firewall or IP routing rules that are set up for IP networks.
- In order to make a network connection using host names, all machines must be able to resolve the host names of DataCore Servers to their IP address. See Name Resolution.
- When a specific IP address is assigned, access will only be allowed on that interface. If the selected IP address changes, the connection will fail. There must be a valid network connection between the specified IP address and the other servers in the local server group, replication partnership or DataCore Management Console or the connection will fail.
- We highly recommend using a connection that is not being used for data traffic. The best practice is to use a dedicated connection and have no port roles assigned to the connection.
To assign a connection interface:
- In the DataCore Server Details page>Settings tab, click the arrow in the Connection interface box and select the interface to use.
- Click Apply to make the configuration change. The connection will disconnect briefly and reconnect using the new interface.
Follow the steps below when a specific port is assigned as the Connection Interface and the IP address of the assigned port needs to be changed.
- In DataCore Server Details page>Settings tab, set the connection interface setting to All.
- Ensure virtual disks are healthy and up-to-date.
- Change the IP address in the name resolution mechanism that you are using for your network configuration, or in the usual manner.
- Ensure proper name resolution exists between each DataCore Server in the server group, remote DataCore Management Consoles.
- If necessary, re-assign the new IP address for the connection interface. The connection will disconnect briefly and reconnect using the new interface.
- Check to be sure that all other DataCore Servers, remote DataCore Management Consoles, and replication partners can access the server with the new IP address.
When replicating virtual disks between two server groups, it is important to rename the server groups to make them unique.
To change server group name: