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Frequently asked questions about HFSQL Cluster
HFSQL Client/ServerAvailable only with this kind of connection
A specific setup package is required to use HFSQL Cluster.
This pack can be downloaded at no extra cost on PC SOFT site, in the download section of modules common to version 28.
QuestionWhat is HFSQL Cluster?
AnswerHFSQL Cluster is a system for managing relational databases intended to be deployed on a group of servers (a cluster) in order to guarantee a high availability. For more details, see Overview of HFSQL Cluster.
QuestionWhat is the link between HFSQL Cluster , HFSQL Client/Server, HFSQL Classic and HFSQL Mobile?
AnswerThese terms are used to identify the different editions of the HFSQL database. All these editions share the same file format which makes evolutions and data transfers very easy. All the editions also share the same statements for accessing the data.
  • HFSQL Cluster: cluster edition intended for critical architecture requiring high accessibility.
  • HFSQL Client/Server: Client/Server edition. The databases are made available to the client applications by a database server.
  • HFSQL Classic: Local or Network edition. The databases are stored in simple files that can be used by a single application on a local computer or that can be shared on a network.
QuestionWhat is the license proposed for using HFSQL Cluster?
AnswerThe HFSQL Client/Server license also applies to HFSQL Cluster.
QuestionDoes HFSQL Cluster require a specific hardware configuration?
AnswerHFSQL Cluster does not require any special investment to be implemented. For more details, see Installing HFSQL Cluster.
QuestionIs HFSQL CLuster intended for a specific type of applications?
AnswerAll types of applications can be addressed by HFSQL Cluster, especially in the fields that require high data availability and/or the fields that require load balancing (Web hosting, ...).
QuestionDo I have to modify my existing HFSQL Client/Server code to use HFSQL Cluster?
AnswerNo. The code is entirely compatible between the different editions of HFSQL. However, in its current version, HFSQL Cluster has a few limitations compared to HFSQL Client/Server (these limitations are listed below). It is very important to run the test of any application intended to be deployed on a cluster before it is implemented.
QuestionHow many physical server are required to create a minimum cluster configuration?
AnswerAt least three physical servers are required to create a configuration of HFSQL cluster: two of them will be the nodes of the cluster, the third one will run the service of the Coordinator (ClusterManager service).
QuestionWhat is the maximum number of nodes in an HFSQL cluster?
AnswerA cluster can manage up to 128 nodes.
QuestionCan the physical servers of a cluster be located in several geographical locations?
AnswerBecause of the throughput required to perform a synchronous replication of the databases, we highly recommend not to dissociate the nodes of a cluster geographically. However, a mechanism for asynchronous replication can be used between two clusters that are geographically distant.
QuestionCan client applications be in 32 and 64-bit?
AnswerClient applications can run on Windows 32 or 64-bit, Linux (32-bit only), and MacOS X (32-bit only), regardless of the version of the cluster (32 or 64-bit).
QuestionHow is HFSQL Cluster managed?
AnswerHFSQL Cluster is managed via the HFSQL Control Center. For more details, see Managing HFSQL Cluster.
QuestionHow to change the major version of the HFSQL engine in the nodes of an HFSQL cluster?
AnswerThe major version of the HFSQL Client/Server engine is changed successively on each node:
  • Stop a node,
  • Update the HFSQL Client/Server engine for the relevant node,
  • Restart,
  • Wait for the node to synchronize before performing the same operation on another node.
QuestionHow is the status of an HFSQL Cluster monitored?
AnswerThe status of the nodes of an HFSQL Cluster can be monitored via the Monitoring Robot.
QuestionAfter changing the file structure in the analysis (adding, changing or deleting items), how to apply the changes to the files on the different cluster nodes?
AnswerSimply apply the structure modification (automatic data modification) to a cluster node.
The HFSQL Cluster synchronization process transfers structure modifications to all the cluster nodes.
QuestionIs it possible to add or remove links?
AnswerStarting with version 27, automatic data modification support is more comprehensive:
QuestionDoes HFSQL Cluster have any limitations?
AnswerThe current version of HFSQL Cluster has the following limitations compared to HFSQL Client/Server.
These limitations will disappear in the forthcoming versions.
  • No bounds of automatic identifier can be defined for the replication.
  • A backup cannot be restored without stopping the cluster.
  • The following functions are not allowed:
    • HAddScheduledOptimization/HModifyScheduledOptimization/HDeleteScheduledOptimization
    • HAddScheduledBackup/HModifyScheduledBackup/HDeleteScheduledBackup/HExecuteScheduledBackup
    • HLoadParameter/HSaveParameter/HDeleteParameter
    • HCopyFile (only the Client to Server syntax and the Server to Server syntax)
    • HCreateServerTrigger/HDescribeServerTrigger/HActivateServerTrigger/HDeactivateServerTrigger/HDeleteServerTrigger
    • HSetServer (the following options are not available: hLogLevel, hMaxLogSize, hActivityStatisticsPeriod, hMaxActivityStatisticsSize, hServerPort, hMode2GB and hDebuggingPort)
    • HManageTask/HAddTask/HModifyTask/HDeleteTask
    • HNoDatabaseAccess/HEndNoDatabaseAccess
    • HNoModif/HEndNoModif
    • HLogRecreate
    • HLogRestore
    • HFree
    • HModifyDatabaseProperty/HModifyFileProperty/HModifyServerProperty
    • HBackup/HDeleteBackup
    • HDeleteFile
    • HDeleteDirectory
    • HDeleteAll
Minimum version required
  • Version 15
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