Creating a mirror

Configuration

Sessions

Sessions - Shows the currently configured sessions. Selecting a session will show the settings associated on the right.

New... - Changes the panels to add a Views server or expand an existing server to select a DataSet for mirroring.

New Session

Create - After configuring all settings, clicking this will create the new mirror session.

Cancel - Clears any configured fields and returns to the Sessions view.

Browse -  Enter the name or IP address of the source Enterprise Historian computer. If access is to be secure then the secure port number of the Views endpoint will need to be appended to the name or IP address.

• Add - Clicking the Add button will add the server to the tree structure below.
• Note: If connecting to a secure endpoint on the source machine then the connection may fail. Go to the Canary Admin on the source machine, click the Views tile then Configuration and Access. An entry will exist on the lower-right panel from the destination machine. Select it and click Allow. Now the new Source address can be added to the Mirror.

Expand the source computer containing the DataSet you want to mirror.  To communicate between systems the Mirror uses the Views Web Service, this will allow you to browse the source computer and select the DataSet you wish to mirror. Properties of the remote DataSet are displayed in the panel below.

Default settings will populate the fields under Settings. See below for descriptions.

Remove - Select a mirror session and click Remove to delete all settings for this mirror.

Settings - Some settings are only shown during creation and cannot be changed later. Other configurable settings are displayed when a mirror session is selected.

Source Address: - Name or IP address of the source Historian computer. If access is to be secure then the secure port number of the Views endpoint will need to be appended to the name or IP address.

Source Historian: - Computer name of the source Historian computer.

Source DataSet: - Name of the DataSet to mirror from the source Historian.

Destination DataSet: - A default DataSet name is generated when a DataSet is selected. This name can be edited to be exactly the same as the source or changed to something different.

Destination Path: - This is the directory location where the new DataSet is to be created.

Snapshot Time: - Determines how often the .hdb files are synced.

Frequency: - Snapshots can be scheduled to occur at normalized intervals from 15 minutes to 12 hours.

Specified: - Snapshots can be scheduled to occur at user defined times. Multiple times during a day can be entered by separating them with a comma ",".

Snapshot Files: -  .hdb2 files to be mirrored to the destination Historian, "All, Last 30 Days, Last 7 Days".

Starting with version 17, the DataSet configuration to delete files older than ??? Days, Months or Years will also be triggered by a Snapshot. Use caution to be sure the 'Snapshot Files:" setting is less than the 'Delete Files' setting. Otherwise, the Snapshot will download files and then delete the ones older than the 'Delete' setting.

Snapshot Throttling (Speed Slower Than 20Mbs) - Allows for control of the "Snapshot" transfer over the communication line.

If the “Snapshot Throttling” is unchecked,  the block size will be 256K with 0 “Interblock Delay”.  The “Compress” is disabled, and the “Snapshot On Start” and “Snapshot On Reconnect” is enabled.

Block Size (KB): and Block Delay (ms): - Depending on the communication link you may need to tune down the snapshot.

By default, it is set to transfer with a block size of 256K and no delay between blocks.

By setting the “delay between blocks” to the approximate time to download a single block, the Comm Usage will be decreased by about half. The overall time to download the .hdb file will increase accordingly.

By decreasing the size of the blocks, you will shorten the time to transfer a single block, but you will increase the number of blocks needed to transfer the entire file.  Theoretically, this allows more network traffic to interleave with the snapshot blocks. On a slow communication link, reduce the block size to 8 or 16K bytes. The ratio is fairly linear, by cutting the block size in half, the time per block will be about half.

On a 10Mb network, setting the block size to 16K, changes the single block time down to 20ms.  Then changing the delay to 20ms changes the Comm Usage % to under 50%.

Compress - Adds additional message compression (similar to zipping). This compression will require additional time to compress before transmitting and then uncompressing afterward. On faster networks, the “message compression” time can take longer than the time saved by reducing the network traffic.

Snapshot On Start - On a critical control network, it may be important to control the exact time that the snapshot occurs. Uncheck this option and set the specific time to snapshot during off hours.

Snapshot On Reconnect - By default the Mirror will automatically Snapshot the files should communication be lost for any length of time. Unchecking this box will disable this functionality especially for a critical control network.

If tags are added to the source dataset,  or the source dataset is rolled-over, a snapshot will occur unless the “Snapshot on Reconnect” is unchecked.

Real-Time Frequency: - Determines how often the mirror updates data values between Snapshots from Never to 60 seconds.

Track Performance - Checking this box will create a tag in the Diagnostics DataSet for this mirror session which tracks the communication speed.