The following table describes the additional information about the settings that are required while creating a file replication rule.
| Setting | Description | Default |
|---|---|---|
| Files to Exclude | Specifies files or directories to exclude from a replication. When specifying a file or directory, enter either:
|
None are excluded. |
| Block-based Replication Minimum File Size | Block replication minimum file size controls the minimum file size that is used for block replication. The list options available are: 256 or 512 K, and 1, 2, 4, 8, 16, 32, 64 or 128 MB. For instance, if this option is set to 64 MB:
|
Minimum file size used for block replication is 32 MB. |
| Use Changed Directory List | Indicates if incremental replications will search for changed files in directories that only contain changed files. Processes not using the changed directory list must search the entire directory tree looking for changed files. When using the changed directory list, however, the search is limited to those directories that contain changed files. Options:
Note: Using the change object list is likely to improve performance in some cases; for example, where there are sparse changes. However, it can degrade performance where there are many changes throughout the directory structure.
The calculation of the change list might take a long time as there can be a long delay between replications. Use Changed Directory List should only be selected if a large part of the directory tree will be unchanged between replication copies. Also, the list can include up to one million directories that contain changed files. If this limit is exceeded the replication reverts to a full hierarchical scan. |
Disabled. |
| Number of Additional Server Connections | Controls the number of additional server connections that are established during a replication operation. Ranges from 0 to 30. Increasing the number of additional server connections might improve performance by allowing multiple transfers in parallel. Note: Each additional server connection consumes system resources, and best practices indicate limiting the number of additional server connections to situations in which they improve performance. Also, as the number of additional server connections is increased, more read-ahead processes are required.
|
Number of additional server connections that are established during a replication operation is four. |
| Number of Read Ahead Processes | Controls the number of read-ahead processes used when reading directory entries during a replication. Each additional read-ahead process uses system resources, so it is best to limit the number of additional processes unless it makes a significant difference in performance. While the default number of read-ahead processes is suitable for most replications, file systems made up of many small files increase the amount of time spent reading directory entries proportionately. In such cases, adding additional read-ahead processes may speed up the replication operation. |
If a value is not set, the default value is set by the application (depending on the number of read-ahead processes set in Number of Additional Server Connections). |
| Pause While Replication(s) Finish Writing | By default, the data management engine imposes an interlock to stop NDMP backups and accelerated data copies (ADCs) from the destination of a replication during active replication writes. This function supports installations that replicate to a particular volume, then back up from that volume. However, as the lock is held at the volume level, it may be useful to override this action in the case of directory-level replication. To make use of this replication interlock, specify this rule option on both the replication that waits and the replication that is waited upon. As a best practice:
|
No |
| Take a Snapshot | Overrides the Backup configuration option Automatic Snapshot Creation. The setting for this option should be left as the system default in almost all cases. The only case in which it might be useful is when taking a single, non-incremental copy of a file system or a directory. If there is insufficient space on the file system to take a snapshot, the copy may be taken from the live file system by selecting Disable. However, it should be noted that copying the live file system while it is changing may give an inconsistent copy. Disabling snapshot usage will affect the ability to run incremental replications. This option should only be set to No if the rule is going to be used for a one-off full replication.
Different files will be copied at different times, so if the source file system is changing and there are dependencies between different files on the system, then inconsistencies may be introduced. Note: Snapshots are an integral part of the algorithm for incremental replication, and disabling snapshot usage will affect the ability to run incremental replications. This option must be enabled in order to make incremental replication copies.
|
Yes. Snapshots are taken and backed up automatically. |
| Delete the Snapshot | Determines when snapshots are deleted. The setting for this option should be left as the system default in almost all cases. The only case in which it might be useful is when taking a single, non-incremental copy of a file system or directory. If the file system is short on space, it may be useful to request the immediate deletion of the snapshot taken for the replication. The deletion options are:
CAUTION: As changing these settings can adversely affect the replication process, Hitachi Vantara recommends that this option be changed only at the direction of your Hitachi Vantara representative.
|
If the replication is an incremental replication, the application automatically selects the correct setting. |
| Migrated File Exclusion | Indicates if the replications will include files whose data has been migrated to secondary storage.
|
Disabled |
| Migrated File Remigration | Controls the action at the destination when the source file had been migrated.
|
Enabled. Re-migration of the files is attempted. |
| Ignore File Attribute Changes | Specifies that files in which the only change is an attribute change, are not included in a replication. Only enable this option if you are certain that you do not want to replicate files with only attribute changes. | Disabled |
| External Migration Links | Controls when a replication operation encounters a cross volume link (a link to a file that has been migrated to an external server).
Note: For externally migrated files, to make sure that the file or link is replicated properly, you should either:
|
Re-migrate |