SIOS SANless clusters High-availability Machine Learning monitoring
Definition: A virtual server or virtual machine (VM) is a software based computer architecture that emulates the user experience of a hardware based server. VMs allow the user to run multiple operating systems on the same physical machine. They allow users to allocate critical resources such as compute, storage, networking as needed without the constraints of physical servers.
Reproduced from SIOS
Definition: In computing, system recovery refers to the process of rebuilding a computer system or restoring data from a secondary source, such as an external hard drive. Because this process can require extended application downtime, mission-critical applications are typically protected with high availability clustering that automatically moves application operation to a different server until the primary system can be fully recovered or replaced.
Reproduced from SIOS
Definition: Similar to system recovery, system restore is the process of returning a computer system to an operating state by restoring files from hard disk and restoring registry, system memory and storage media. Microsoft Windows Server environments System Restore feature can return a system operation using snapshots of some system settings, allowing you to revert to specific files and settings without reinstalling the entire operating system.
Reproduced from SIOS
I often help people automate the configuration of their infrastructure so they can build 3-node clusters that span Availability Zones and Regions. The CLI for creating a DataKeeper Job and associated mirrors that contain more than one target can be a little confusing, so I’m documenting it here in case you find yourself looking for this information. The DataKeeper documentation describes this as a Mirror with Multiple Targets.
The environment in this example looks like this:
PRIMARY (10.0.2.100) – in AZ1
SECONDARY (10.0.3.100) – in AZ2
DR (10.0.1.10) – in a different Region
I want to create a synchronous mirror from PRIMARY to SECONDARY and an asynchronous mirror from PRIMARY to DR. I also have to make sure the DataKeeper Job knows how to create a mirror from SECONDARY to DR in case the SECONDARY or DR server ever become the source of the mirror. EMCMD will be used to create this multiple target mirror.
We need to first create the Job that contains all this possible endpoints and define whether the mirror will be Sync (S) or Async (A) between those endpoints.
emcmd . createjob ddrive sqldata primary.datakeeper. local D 10.0.2.100 secondary.datakeeper. local D 10.0.3.100 S primary.datakeeper.local D 10.0.2.100 dr. datakeeper.local D 10.0.1.10 A secondary.datakeeper.local D 10.0.3.100 dr.datakeeper. local D 10.0.1.10 A
That single “createjob” command creates the Job. It might be a little easier to look at that command like this:
emcmd . createjob ddrive sqldata primary.datakeeper.local D 10.0.2.100 secondary.datakeeper.local D 10.0.3.100 S primary.datakeeper.local D 10.0.2.100 dr.datakeeper. local D 10.0.1.10 A secondary.datakeeper.local D 10.0.3.100 dr.datakeeper.local D 10.0.1.10 A
Next we need to create the mirrors.
emcmd 10.0.2.100 createmirror D 10.0.1.10 A emcmd 10.0.2.100 createmirror D 10.0.3.100 S
Our DataKeeper Job should now look like this in the DataKeeper UI
One-to-many DataKeeper Replicated VolumeAnd then finally we can register the DataKeeper Volume Resource in the cluster Available Storage with this command.
emcmd . registerclustervolume D
The DataKeeper Volume Resource will now appear in Available Storage as shown below.
DataKeeper Volume in Available StorageYou are now ready to install SQL Server, SAP, File Server or any other clustered resource you normally protect with Windows Server Failover Clustering.
Reproduced with permission from Clusteringformeremortals
Definition: When clustering software detects a failure in the primary cluster node, it moves operation of the SQL Server to the secondary node in the cluster in a process called failover. Since the secondary node has access to the same data as the primary node, operation continues without downtime or data loss.
Reproduced from SIOS