In the same way that file replication policies specify the details about file replication operations, object replication policies specify the details about object replication operations.
Adding object replication policies
The Add Object Replication Policy pages allow you to define the properties of a new object replication policy, including its source file system and its replication target (server/cluster, EVS, and file system).
If this is the first policy created, and if the file system is not configured to transfer access points with a replication, then the option to manually configure the file system to transfer access points will be given. You are provided with more resolution options on the second Add Object Replication Policy page.
Specify the details for the policy identification, replication source and the replication target.
Click next to continue with the policy configuration.The replication process checks if the source file system is configured to allow the access points (SMB shares and NFS exports) on it to transfer with the object replication. If it is not, a NAS Manager page is displayed that gives you the option of configuring the source file system so it can transfer shares and exports with the replication. If another policy already exists for this file system, the check for access point transferability is skipped, and the second part of the Add Object Replication Policy page is displayed:
The policy can result in two types of replications of the source file system: an initial replication, and an incremental replication. A replication of an initial snapshot results in a full copy of the source file system being replicated on the target, while subsequent replications use an incremental snapshot that only copies objects that have changed since the initial snapshot was taken.
When setting snapshot rules, you can choose either an automatic snapshot rule or an existing, named rule.
In order to avoid snapshots being taken of inconsistent data, please carefully note the following recommendations:
- If you choose the automatic snapshot rule option, the snapshot is taken whenever the replication first runs. In order for the replication engine to take a snapshot with consistent data (that is, data that is not actively being modified on the source file system), it is recommended that the replication be run when the file system is not being actively accessed. For example, the replication can be run manually, when the source file system is inactive, to obtain a snapshot with consistent data. Or, the replication policy should be scheduled to run when the file system is not being accessed.
- If you choose a named snapshot rule, the snapshot is taken when specified by the rule; however, it is recommended that the snapshot is taken manually, when the file system is not being actively accessed, or scheduled to be taken when such a time is anticipated. Then the replication should be scheduled at a time when the server is minimally active, or run manually at such a time.
The following table describes the fields on the second Add Object Replication Policy page:Note If a database application is writing to its database when a snapshot is taken, the snapshot can contain only some of the writes to the database, rather than all of them. In such a case, the database might contain only partially written records and is therefore not consistent.CautionSetting the snapshot options for the source and target file systems must be done very carefully, to ensure that replications provide a good copy of the data on the target. It is recommended that you consult with support representative if you are unsure of how to correctly set snapshot options for an object replication.
Field/Item Description Source File System Options for taking snapshots of the source file system:
- Snapshot source file system using automatic snapshot rule, which allows the replication to use its default snapshot rule to take and manage snapshots.
NoteIf you choose this option, each incremental snapshot is deleted when the next replication runs. Therefore, because the snapshot queue only contains one snapshot, it is recommended that replications are not scheduled too closely together in order to prevent an existing snapshot from being removed before the next replication starts.
- Use snapshot rule, which means that the source snapshot retention policy can be customized to retain a different number of snapshots on the source file system.
NoteIf you choose this option, set the schedule for the snapshot rule so a snapshot is created before the replication runs, to ensure that a new snapshot is available for the replication. A snapshot of the source file system is only taken if the replication policy is configured to use an automatic snapshot rule. If it is using a named rule, the replication will use the latest snapshot created by that rule; it does not take one automatically.
Target File System Options for taking snapshots of the target file system:
- Snapshot target file system using automatic snapshot rule, which allows the replication to use its default snapshot rule to take and manage snapshots on the object replication target.
- Use snapshot rule, which allows the snapshot retention policy to be customized to retain a different number of snapshots on the source and destination.
Enter the processing options.
Click next to advance to the Add Object Replication Policy page.NoteThe source and target file systems are evaluated and, if any issues are detected, a page appears listing them and offering options to help you either correct the issue or to go back to the previous page.
Review policy settings, and then click create.
To add a schedule for this policy, click yes to display the Add Object Replication Schedule page.
Correcting access point problems in an object replication policy
Before a new object replication policy is created, it is evaluated for potential problems, such as the source not being configured to allow the transfer of access points (SMB shares or NFS exports). If an issue is discovered, a page appears, offering options to correct the issue or to go back to a previous page, where you can make changes to resolve the issue.
Typically, when this page appears, the following links are displayed:
- Configure: Click
configure to automatically configure the selected source file system and continue creating the policy.
Clicking this link configures the selected file system to allow the access points on it to be transferred with an object replication. After clicking this link, you are returned to the previous page to continue the configuration.
- Change: Click change to return to the previous page, in which you can select another file system as the source of the object replication.
- Continue: Click continue to continue configuring the object replication policy using the selected file system, even though that file system is not configured to allow the access points to be transferred with an object replication. You must later explicitly set the shares and exports to be transferred with the object replication at a later time.
To manually override the default, you must manually reset the shares and exports from the File Services link on the replication process Home Page. Since there may be many individual settings for shares and exports on that page, it is recommended that you choose the Configure link on this page instead, which automatically configures the file system to allow shares and exports without further steps.