Evidian > Products > High Availability Software - Zero Extra Hardware > Shared nothing cluster vs shared disk cluster
Shared nothing cluster |
Shared disk cluster |
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Clustering toolkit for shared disk |
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Extra hardware |
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No - Use internal disks of servers |
Yes - Extra cost with a shared bay of disks |
Application data organization |
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0 impact on application data organization with SafeKit. Just define directories to replicate in real-time. Even directories inside the system disk can be replicated. |
Impact on application data organization. Special configuration of the application to put its data in a shared disk. Data in the system disk cannot be recovered. |
Complexity of deployment |
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No - install a software on 2 servers |
Yes - require specific IT skills to configure OS and shared disk |
Failover |
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Just restart the application on the second server. |
Switch the shared disk. Remount the file system. Pass the recovery procedure on the file system. And then restart the application. |
Disaster revovery |
Just put the 2 servers in 2 remotes sites connected by an extended LAN. |
Extra cost with a second bay of disks. Specific IT skills to configure mirroring of bays across a SAN. |
Quorum and split brain |
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Application executed on a single server after a network isolation (split brain). Coherency of data after a split brain. No need for a third machine or a quorum disk or a special heartbeat line for split brain. |
Require a special quorum disk or a third quorum server to avoid data corruption on split brain |
Suited for |
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Software editors which want to add a simple high availability option to their application |
Enterprise with IT skills in clustering and with large database applications |
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Application High Availability vs Full Virtual Machine High Availability > |
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Byte-level file replication vs block-level disk replication > |
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Virtual IP address |
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Evidian SafeKit mirror cluster with real-time file replication and failover |
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Fully automated failback procedure > |
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Replication of any type of data > |
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File replication vs disk replication > |
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File replication vs shared disk > |
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Remote sites and virtual IP address > |
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Uniform high availability solution > |
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Evidian SafeKit farm cluster with load balancing and failover |
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No load balancer or dedicated proxy servers or special multicast Ethernet address > |
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Remote sites and virtual IP address > |
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Uniform high availability solution > |
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This platform agnostic solution is ideal for a partner with a critical application and who wants to provide a high availability option easy to deploy to many customers.
Network load balancing and failover |
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Windows farm |
Linux farm |
Generic farm > | Generic farm > |
Microsoft IIS > | - |
NGINX > | NGINX > |
Apache > | Apache > |
Amazon AWS farm > | Amazon AWS farm > |
Microsoft Azure farm > | Microsoft Azure farm > |
Google GCP farm > | Google GCP farm > |
Other cloud > | Other cloud > |
Several modules can be deployed on the same cluster. Thus, advanced clustering architectures can be implemented: