Stopping, starting, pausing, or resuming mirroring

After a connection is established, you need to be able to control the mirroring. You can start, stop, pause and resume mirroring. open the Replication Console, and right-click the connection on the right pane of the Replication Console. Select Mirroring and the appropriate mirror control.

Pause or Resume—When pausing a mirror, Double-Take Availability stops queuing mirror data on the source but maintains a pointer to determine what information still needs to be mirrored to the target. Therefore, when resuming a paused mirror, the process continues where it left off.

Stop—When stopping a mirror, Double-Take Availability stops queuing mirror data on the source and does not maintain a pointer to determine what information still needs to be mirrored to the target. Therefore, when starting a mirror that has been stopped, the process will mirror all of the data contained in the replication set.

Start—If you select to start a mirror, you will need to make the following two selections on the Start Mirror dialog box.

Full Mirror—All files in the replication set will be sent from the source to the target.

File differences—Only those files that are different based size or date and time will be sent from the source to the target. Expand File difference mirror options compared below to see how the file difference mirror settings work together, as well as how they work with the global checksum setting on the Source tab of the Server Properties.

Send data only if Source is newer than Target—Only those files that are newer on the source are sent to the target.

Note:

If you are using a database application, do not use the newer option unless you know for certain you need it. With database applications, it is critical that all files, not just some of them that might be newer, get mirrored.

Use block checksum—For those files flagged as different, the mirror performs a checksum comparison and only sends those blocks that are different.

Calculate Replication Set size prior to mirror—Determines the size of the replication set prior to starting the mirror. The mirroring status will update the percentage complete if the replication set size is calculated.

File difference mirror options compared

Server Properties Source Tab	Connection Manager Mirroring Tab or Start Mirror Dialog			Action Performed
Checksum All	File Differences	Only if Source is Newer	Checksum	Action Performed
(X)	X			Any file that is different on the source and target based on the date, time, and/or size is transmitted to the target. The mirror sends the entire file.
(X)	X	X		Any file that is newer on the source than on the target based on date and/or time is transmitted to the target. The mirror sends the entire file.
	X		X	Any file that is different on the source and target based on date, time, and/or size is flagged as different. The mirror then performs a checksum comparison on the flagged files and only sends those blocks that are different.
X	X		X	The mirror performs a checksum comparison on all files and only sends those blocks that are different.
(X)	X	X	X	Any file that is newer on the source than on the target based on date and/or time is flagged as different. The mirror then performs a checksum comparison on the flagged files and only sends those blocks that are different.