HP UX Serviceguard Storage Management Software Benefits and Applications, Advantages To Using CFS

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Technical Overview

Benefits and Applications

Benefits and Applications

The following sections describe CFS benefits and some applications.

Advantages To Using CFS

CFS simplifies or eliminates system administration tasks resulting from hardware limitations:

The CFS single file system image administrative model simplifies administration by allowing all file system management operations, resizing, and reorganization (defragmentation) to be performed from any node.

You can create and manage terabyte-sized volumes, so partitioning file systems to fit within disk limitations is usually not necessary - only extremely large data farms must be partitioned to accommodate file system addressing limitations. For maximum supported file system sizes, see Supported File and File System Sizes for HFS and JFS available at: http://docs.hp.com/en/oshpux11iv3.html#VxFS

Keeping data consistent across multiple servers is automatic, because all servers in a CFS cluster have access to cluster-shareable file systems. All cluster nodes have access to the same data, and all data is accessible by all servers using single server file system semantics.

Applications can be allocated to different servers to balance the load or to meet other operational requirements, because all files can be accessed by all servers. Similarly, failover becomes more flexible, because it is not constrained by data accessibility.

The file system recovery portion of failover time in an n-node cluster can be reduced by a factor of n, by distributing the file systems uniformly across cluster nodes, because each CFS file system can be on any node in the cluster.

Enterprise storage arrays are more effective, because all of the storage capacity can be accessed by all nodes in the cluster, but it can be managed from one source.

Larger volumes with wider striping improve application I/O load balancing. Not only is the I/O load of each server spread across storage resources, but with CFS shared file systems, the loads of all servers are balanced against each other.

Extending clusters by adding servers is easier because each new server’s storage configuration does not need to be set up - new servers simply adopt the cluster-wide volume and file system configuration.

For the following HP Serviceguard Storage Management Suite CFS for Oracle bundles, the clusterized Oracle Disk Manager (ODM) feature is available to applications running in a cluster, enabling file-based database performance to approach the performance of raw partition-based databases:

T2776CA, T2777CA, T2796CA, and T2797CA

T2776CB, T2777CB, T8686CB, T8687CB, T8696CB, and T8697CB

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Contents Second Edition Legal Notices Contents Cluster Volume Manager Administration TroubleshootingPrinting History Printing HistoryPage Technical Overview Overview of Cluster File System Architecture Cluster File System DesignCluster File System Failover Group Lock ManagerSupported Features CFS Supported FeaturesVxFS Functionality on Cluster File Systems Unsupported Features CFS Unsupported FeaturesCFS Unsupported Features Advantages To Using CFS Benefits and ApplicationsWhen To Use CFS Benefits and Applications Chapter Cluster File System Architecture Veritas Cluster Volume Manager Functionality Role of Component ProductsCluster Communication Membership PortsAbout CFS Cluster File System and The Group Lock ManagerAsymmetric Mounts Parallel I/O Primary and Secondary Mount OptionsCluster File System Backup Strategies Error Handling Policy Synchronizing Time on Cluster File SystemsDistributing Load on a Cluster File System TuneablesAbout Veritas Cluster Volume Manager Functionality Example of a Four-Node ClusterPrivate and Shared Disk Groups Activation Modes for Shared Disk Groups Activation Modes for Shared Disk GroupsConnectivity Policy of Shared Disk Groups Allowed and conflicting activation modesLimitations of Shared Disk Groups About Veritas Cluster Volume Manager Functionality Chapter Cluster File System Administration Cluster File System Administration Cluster Messaging GAB Cluster Communication LLT Volume Manager Cluster Functionality Overview Cluster File System Overview Cluster and Shared MountsAsymmetric Mounts Cluster File System Administration Cluster File System CommandsTime Synchronization for Cluster File Systems Growing a Cluster File SystemFstab file Distributing the Load on a ClusterCluster File System Administration Cluster Snapshot Characteristics Snapshots for Cluster File SystemsPerformance Considerations Creating a Snapshot on a Cluster File System# cfsumount /mnt1snap Cluster Volume Manager Overview of Cluster Volume Management Example of a 4-Node Cluster Disk group activation mode restrictions Either of the write modes on other nodes will fail # cfsdgadm display Disk Group Failure Policy Behavior of Master Node for Different Failure PoliciesRecovery in a CVM Environment Troubleshooting Installation Issues Inaccessible SystemIncorrect Permissions for Root on Remote System Resource Temporarily UnavailableInstallation Issues Cluster File System Problems Unmount FailuresMount Failures Command Failures Performance IssuesHigh Availability Issues Cluster File System Problems Appendix a