The DataCore Server Settings
Operating System Type
When registering the Host choose one of the appropriate options:
- Windows 2022 / 2019 / 2016 choose 'Microsoft Windows 2012 and later’
Only available with SANsymphony 10.0 PSP 6 or later for SANsymphony 10.0 PSP5 and earlier use ‘Microsoft Windows 2012’. - All earlier Windows versions choose ‘Microsoft Windows’
Port Roles
Ports that are used to serve Virtual Disks to Hosts should only have the Front End role checked. While it is technically possible to check additional roles on a Front End port (i.e. Mirror and Backend), this may cause unexpected results after stopping the SANsymphony software.
Any port with front-end role (and is serving Virtual Disks to Hosts) also has either the mirror and/or backend role enabled will remain ‘active’ even when the SANsymphony software is stopped. There is some slight difference in behavior depending on the version of SANsymphony installed.
- SANsymphony 10.0 PSP 7 and Earlier
Any port that has the mirror and/or back-end role checked will remain ‘active’ after the SANsymphony software has been stopped.
- SANsymphony 10.0 PSP 8 and Later
Only ports with the back-end role checked will remain ‘active’ after the SANsymphony software has been stopped.
Front-end ports that are serving Virtual Disks but remain active after the SANsymphony software has been stopped can cause unexpected results for some Host operating systems as they continue to try to access Virtual Disks from the ‘active’ port on the now-stopped DataCore Server. This, in turn, may end up delaying Host fail-over or result in complete loss of access from the Host’s application/Virtual Machines.
Multipathing
The Multipathing Support option should be enabled so that Mirrored Virtual Disks or Dual Virtual Disks can be served to Hosts from all available DataCore FE ports. Also see the Multipathing Support section from the SANsymphony Help.
Non-mirrored Virtual Disks and Multipathing
Non-mirrored Virtual Disks can still be served to multiple Hosts and/or multiple Host Ports from one or more DataCore Server FE Ports if required; in this case the Host can use its own multipathing software to manage the multiple Host paths to the Single Virtual Disk as if it was a Mirrored or Dual Virtual Disk.
ALUA Support
The ALUA support option (Asymmetrical Logical Unit Access) should be enabled if required and if Multipathing Support has been enabled (see above). Please refer to the Compatibility Lists table to see which combinations of Microsoft Windows and SANsymphony support ALUA.
More information on Preferred Servers and Preferred Paths used by the ALUA function can be found in Appendix A.
Serving Virtual Disks
For the first time
DataCore recommends that before serving Virtual Disks for the first time to a Host, that all DataCore Front-End ports on all DataCore Servers are correctly discovered by the Host first. Then, from within the SANsymphony Console, the Virtual Disk is marked Online, up to date and that the storage sources have a host access status of Read/Write.
To more than one Host port
DataCore Virtual Disks always have their own unique Network Address Authority (NAA) identifier that a Host can use to manage the same Virtual Disk being served to multiple Ports on the same Host Server and the same Virtual Disk being served to multiple Hosts.
While DataCore cannot guarantee that a disk device's NAA is used by a Host's operating system to identify a disk device served to it over different paths generally we have found that it is. And while there is sometimes a convention that all paths by the same disk device should always using the same LUN 'number' to guarantees consistency for device identification, this may not be technically true. Always refer to the Host Operating System vendor’s own documentation for advice on this.
DataCore's Software does, however always try to create mappings between the Host's ports and the DataCore Server's Front-end (FE) ports for a Virtual Disk using the same LUN number where it can. The software will first find the next available (lowest) LUN 'number' for the Host-DataCore FE mapping combination being applied and will then try to apply that same LUN number for all other mappings that are being attempted when the Virtual Disk is being served. If any Host-DataCore FE port combination being requested at that moment is already using that same LUN number (e.g. if a Host has other Virtual Disks served to it from previous) then the software will find the next available LUN number and apply that to those specific Host-DataCore FE mappings only.
To Microsoft Cluster nodes
Define one Host for each Windows cluster node in the SANsymphony Management Console – i.e. do not create a single Host entry to represent all the nodes in a cluster.
Cluster nodes that have more than one port connected to one or more DataCore Servers will also require additional fail-over software (i.e. MPIO) to be able to failover between its own connected ports rather than just to another cluster node.
DataCore recommend that you run the ‘Validate Configuration’ wizard each time new Virtual Disks are served before they are used for production data to confirm that they will function correctly.
Also see: