Home
Administering
Learn how to administer the product.
Administering HCL Compass Multisite
Administering HCL Compass Multisite
Introduction
HCL VersionVault MultiSiteHCL Compass MultiSite adds a powerful capability to HCL VersionVaultHCL Compass. With MultiSite, developers at different locations can use the same HCL VersionVault versioned object base (VOB) HCL Compass database set (a schema repository and its associated user databases). For HCL VersionVault, each location (site) has its own copy (replica) of the VOB. For HCL Compass, each location has its own copies, or replicas, of the schema repository and user databases. At any time, changes made in one replica can be sent in update packets to other replicas. You can manage replicas by using the command-line tools.
Replica synchronization in a family
Because information in a replicated VOBHCL Compass database is modified concurrently at different replicas, the contents of each replica in a family tend to differ. The contents of a particular replica may never be identical to the contents of any other replica. To keep the replicas from differing too much, each replica sends updates to one or more other replicas. Updating a VOB replica changes both its database and its storage pools to reflect the development activity that has taken place in one or more other replicas.
Operation logs for databases
Most changes to a replicated database are recorded as entries in an operation log (oplog). These entries store all the information required to replay the changes in another replica.

Operation logs for databases

Most changes to a replicated database are recorded as entries in an operation log (oplog). These entries store all the information required to replay the changes in another replica.

The information included in the oplog is as follows:

The identity of the replica in which the change originated.
The specific changes to a database record or to a schema in the schema repository made during a single checkout; for example, submission of a new record, schema updates, and so on.
An integer sequence number: 1 for the first change originating at a particular replica, 2 for the next change, and so on. This is called the oplog ID of the oplog entry.

The exact kind and amount of information varies with the specific operation. For example, an oplog entry for the submission of a new record has different, and more, information than an oplog entry for modifying an existing record.

Note: You can delete a replica’s oplog entries after they have been used to update other replicas.

You do not need the following topics to use MultiSite, but it is helpful when you want to deepen your understanding of the error-recovery facilities.