The XenServer Disaster Recovery (DR) feature is designed to allow you to recover virtual machines (VMs) and vApps from a catastrophic failure of hardware which disables or destroys a whole pool or site. For protection against single server failures, you can use XenServer High Availability to have VMs restarted on an alternate server in the same pool.
Understanding XenServer DR XenServer DR works by storing all the information needed to recover your business-critical VMs and vApps on storage repositories (SRs) that are then replicated from your primary (production) environment to a backup environment.
You can back up a managed server to a XenServer backup file (.xbk) that can then be used to restore the server in case of hardware failure. Note that this will back up just the server itself, but not any VMs that might be running on it.
We recommend that you back up your servers frequently to enable you to recover from possible server and/or software failure. When backing up servers in XenCenter, note the following points:
You enable HA for a resource pool using the Configure HA wizard. The wizard takes you through the HA configuration process, step-by-step, calculating the server failure limit for the pool given the available resources and the HA restart priorities you specify.
To open the Configure HA wizard: in XenCenter, select the pool, click on the HA tab, and then click Configure HA.
Alternatively:
On the Pool menu, click High Availability. Right-click in the Resources pane and then click High Availability on the shortcut menu.
Use the XenCenter Configure DR dialog box to identify storage repositories (SRs) where the metadata for a pool - configuration information about all the VMs and vApps in the pool - will be stored. This metadata will be updated whenever you make changes to VM or vApp configuration within the pool.
To configure DR on the primary pool:
On your primary site, select the pool that you want to protect and on the Pool menu, point to Disaster Recovery and then click Configure.
Minimum 3 XS hosts Shared Storage Resource Pool Static IP address for all Xenserver hosts Advanced edition or higher VMs connected to pool-wide networks VMs not connected to any XS host DVD drive configuration All VM virtual disks on shared storage accessible pool-wide 4 MB heartbeat volume 256 MB metadata volume -stores pool master metadata use bonded management interface VM Restart Priority:
HA restart priority -Restart -Restart if possible -Do not restart
If more servers fail than have been planned for, then an HA recovery operation begins. The HA restart priority is used to determine which VMs are restarted, while the order in which individual VMs are started is determined by their start order and delay interval values, ensuring that the most important VMs are restarted first.
HA restart priority The HA restart priority specifies which VMs will be restarted under the HA failure plan for a pool:
Automatically installed on all XS hosts Included with XenCenter Available as standalone remote CLI-Linux Available for install on windows SSL Connectivity Runs against pool master server Runs against any host member by using host id. Monitoring XenServer
Alerts visible from XenCenter GUI Can be emailed to resource pool admin Can support custom fields and tags Can support custom searches Use XENTOP tool to monitor XS in real time Events and Alerts
XenServer High Availability (HA) allows virtual machines to automatically be restarted in the event of an underlying hardware failure or loss of any managed server. HA is about making sure that important VMs are always running in a resource pool. With HA enabled, if one of your servers fails, its VMs will be intelligently restarted on other servers in the same pool, allowing essential services to be restored in the event of system or component failure with minimal service interruption.
Before configuring the below steps, make sure you add some additional hard disk(I mean space) to your freenas machine.
Open a browser and login to FreeNAS 8.2.
Navigate to Storage > Active Volumes: Click Volume Manager.
Enter a Volume Name, select disk(s), select Filesystem type (ZFS has some neat features), then click Add Volume:
Click the Create ZFS Volume button: Enter a ZFS Volume Name, specify the volume size, then click Add ZFS Volume: Navigate to Services > Core, and turn on iSCSI:
Workload Balancing is a XenServer appliance that balances your pool by relocating virtual machines onto the best possible servers for their workload in a resource pool. For example, Workload Balancing can:
Balance virtual-machine workloads across hosts in a XenServer resource pool Determine the best host on which to start a virtual machine Determine the best host on which to power on a virtual machine that you powered off Determine the best host for each of the host’s virtual machines when you put that host into Maintenance mode Note: Workload Balancing is available in Citrix XenServer Enterprise Edition or higher.
