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Measures reported by DTConnectionTest
IProtecting specific data consists of two main tasks - creating a replication set (to identify the data to protect) and connecting that replication set to a target. A unique connection ID is associated with each target a replication set connects to. The connection ID provides a reference point for each connection. The connection ID is determined by sequential numbers starting at one (1). Each time a connection is established, the ID counter is incremented. It is reset back to one each time the Double- Take service is restarted. For example, if the Double-Take service was started and the same replication set was connected to five target machines, each connection would have a unique connection ID from 1 to 5.
This test monitors the current state of each Double-Take Availability connection and reports the level of activity on each connection, so that the busiest/overloaded connections are revealed, and the operation (mirroring/replication) that is causing the overload can be identified.
The measures made by this test are as follows:
| Measurement |
Description |
Measurement Unit |
Interpretation |
| Conn_Time |
Indicates the amount of time this connection has been active. |
Minutes |
A very high value for this measure could indicate that the data is taking too long to be transmitted to the target. |
| Conn_State |
Indicates the current state of this connection. |
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The values reported by this measure, their description, and the numeric values that correspond to them have been discussed in the table below:
| Measure Value |
Numeric Value |
Measure Description |
| conError |
0 |
A transmission error has occurred. Possible errors include a broken physical line or a failed target service. |
| conActive |
1 |
Indicates that the connection is functioning normally and has no scheduling restrictions imposed on it at this time. (There may be restrictions, but it is currently in a state that allows it to transmit.) |
| conPaused |
2 |
Indicates a connection that has been paused. This implies that the network connection exists and is available for data transmission, but the replication and mirror data is being held in a queue and is not being transmitted to the target. |
| conScheduled |
3 |
Indicates a connection that is not currently transmitting due to scheduling restrictions (bandwidth limitations, time frame limitations, and so on). |
| conNone |
4 |
Indicates that a connection has not been established. |
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| ReTransmit_Opse |
Indicates the number of operations (create, modify, or delete) currently in the retransmit queue on the source. |
Number |
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| Waiting_Ack_Ops |
Indicates the number of operations currently waiting in the acknowledgement queue. |
Number |
Each operation that is generated receives an acknowledgement from the target after that operation has been received by the target. This statistic indicates the number of operations that are yet to receive acknowledgement of receipt. |
| Replication_Ops |
Indicates the number of replication operations currently waiting to be executed on the target. |
Number |
Replication is the real-time transmission of file changes to a target. These changes, instead of being replicated to a target, may be queued to disk, if a locked file on the target prevents the changes from being written to it, or if a file on the source changes faster than can be transmitted to the target. Typically, if the system memory allocated to queueing is utilized fully, then new file changes that are to be replicated to a target will be directly queued to disk, while old changes remain in the system memory. Data queued to disk is written to a transaction log.
The value of this measure indicates the number of file changes that are in queue, and are yet to be replicated to the target. A high value of this measure may indicate that too many file changes are awaiting processing or that one/more files on the target have been locked for too long a time. |
| Mirror_Ops |
Indicates the number of mirroring operations currently in queue. |
Number |
Mirroring is the process of transmitting user-specified data from the source to the target, so that an identical copy of data exists on the target. When Double-Take Availability initially performs mirroring, it copies all of the selected data, including file attributes and permissions. Mirroring creates a foundation upon which Double-Take Availability can efficiently update the target server by replicating only file changes.
A high value of this measure indicates that many mirroring operations are pending processing, which could hint at a probable processing bottleneck. |
| Replication_Data |
Represents the amount of data that was associated with the queued replication operations during the last measurement period. |
KB |
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| Mirror_Data |
Represents the amount of data that was associated with the queued mirror operations during the last measurement period. |
KB |
|
| Ops_Transmitted |
Indicates the total number of operations that are currently transmitted to the target. |
Number |
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| Bytes_Transmitted |
Indicates the total number of bytes sent to the target since the last measurement period. |
KB |
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| Ops_Received |
Indicates the total number of operations (create, modify, or delete) currently received from the target. |
Number |
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| Bytes_Received |
Indicates the total number of bytes received from the target during the last measurement period. |
KB |
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| Resent_Ops |
Indicates the number of operations that were resent because they were not acknowledged. |
Number |
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