## 8.4.1.1 Example: Monitoring SAP HANA System Replication with the SAP HANA Cockpit
Learn how to monitor multiple SAP HANA systems with the SAP HANA cockpit.
In the SAP HANA cockpit, you can monitor system replication using the system replication tile, the system replication overview, and the tabs on the system replication overview.
## System Replication Tile
If system replication is configured, the corresponding tile appears on the main screen of the system overview page providing information about the type of landscape (tier 2 or tier 3), the replication modes between the primary and the secondary systems, the operation mode, as well as an overall replication status. For examples, see System Replication Tile . If all tiers are shown in green and the system replication tile indicates that all services are active and in sync, your system is doing well. Red tiers would indicate a problem with the replication.
If the tile does not show up, you have to grant the system replication specific role to the corresponding user.
## System Replication Overview
To check the status of replication in detail, open the system replication tile. The application provides an overview on the system replication configuration and status. The 'chain' of systems with their replication modes is also displayed containing further information about the sites and the network connections between them.
For example, the system replication overview can look like this:
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A graphical representation of your system replication landscape is given. It tells you the chosen system names, the replication mode used between the systems, as well as how long it took on average to send redo log buffers to the secondary system based on measurements from the last 24 hours. For a synchronous replication, this is the round trip time for sending the redo log buffer and receiving the acknowledgement; for an asynchronous replication it refers to the time that it takes until the log buffer was sent after its creation.
## Related Alerts Tab
If a system replication relevant alert occurred, the first tab is the Related Alerts tab.
If no system replication relevant alert exists, this tab is not shown.
## Replicated Services Tab
In the Replicated Services tab, an excerpt of the M\_SERVICE\_REPLICATION monitoring view is shown. The displayed table shows the replication state for each system and service.
For example, the tab can look like this:
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##  Recommendation
If you want to look at the trace files of all systems in your system replication landscape, choose the View trace and diagnostic files link on the primary system's overview page in the SAP HANA cockpit. This makes all diagnosis files from the trace directories of all systems visible in the browser.
To see the details for the corresponding service grouped thematically, choose one row like in the following example for one indexserver. Since this information is context aware, you only get the information required for this system. For example, because this system is running with the logreplay operation mode, no information on delta data shipping is shown here. However, the context-sensitive information about the log replay
delay is displayed. The delta between Last Log Position and Replayed Log Position indicates how far the log replay is behind on the secondary system:
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## Network Tab
You can select the network connection that you want to analyze from the drop down menu. This can be Network Site 1 to 2 or Network Site 2 to 3 . The displayed graphic compares the local write wait time (writing redo log buffer into the local log volume) with the remote write wait time (shipping the redo log and receiving the acknowledgement) monitored over the last 24 hours. You can see if peak times occurred and how the network connection reacted.
## For example:
RELATED ALERTS
REPLICATED SERVICES
Network Site 1 to 2
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If the ASYNC replication mode is configured between two systems, you also receive information about the network performance by selecting the corresponding connection between tier 2 and tier 3. For example:
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## Buffer Write Wait Time Log
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In this example, the average write wait time in ms describes the time it took from the creation of the redo log buffer (committing a write transaction) until the redo log buffer was sent out to the network. This value is an indicator for peak load phases and could point to network or I/O problems on the secondary system, which can influence the primary's performance as well.
For more information, see Monitoring the Network Latency .
NETWORK
LOG REPLAY
## Log Replay Tab
This tab is only visible, if logreplay or logreplay\_readaccess is configured for the system replication landscape. The log replay delay on the secondary system is displayed as size in GB for the last 24 hours. If at some point in time, the threshold of the corresponding alert (for example, ID 94 System Replication Logreplay Backlog) was exceeded, this is indicated accordingly. For example:
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For more information on how to analyze a high replay backlog, see SAP Note 2409671: High replay backlog on HANA System Replication Secondary Site .
Additionally, you can select the log retention information for your system. For more information, see Estimating the Maximum Retention Time .
## Network Speed Check
To measure the network speed for system replication, host-to-host mappings from the primary system to the secondary system (and even to a third tier) can be done using the Network Speed Check (System Replication Communication) tab.
To measure the network speed (MB/s), choose a package size from the drop-down menu and choose Measure Network Speed .
In this example, there are standby hosts configured on the primary (ha-test-03) and the secondary (hatest-06) system. The network speed measurement cannot be done for standby hosts, because they do not
have access to the data and log volumes of the SAP HANA database and thus are not relevant for replication in this state:
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You can also measure the network speed for scale-out SAP HANA databases using the Network Speed Check (Internal Communication) tab. It measures the network speed in both directions for each host to each other host of the scale-out system. To do so, choose a package size from the drop-down menu and choose Measure Network Speed . The result is a list representing the network speed for every host in the scale-out system to every other host of the system. The measurement is done in both directions. Thus, every host-mapping is displayed twice in this list with switched roles of Sender and Receiver . The fastest connection is displayed first.
##  Note
Measuring the network speed of your SAP HANA system replication communication channels or internode communication channels in your SAP HANA scale-out system will have an impact on your network performance and thus on your running systems for the time of the measurement.
## Network Security Settings
This tab shows the security details configured between the primary and the secondary systems:
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## Related Information
Estimating the Maximum Retention Time [page 23]
```
System Replication Tile [page 40] Monitoring the Network Latency [page 192] SAP Note 2409671
```