Handling Files, Datasources, and the Network
Network Failure/Non-Availability

In case of a sudden network failure or crash of the network server

If the network fails during data acquisition, acquisition on a remote Chromeleon Server is not interrupted. The data acquired during the network failure can be written back to the network datasource sometime later.

 Tip: 

If the network fails while Chromeleon is accessing an Access database, the Chromeleon datasource (mdb file) may be damaged. Therefore, Dionex recommends using an MS SQL or Oracle server as the central database to ensure that data are protected even if the network fails.

After a network failure, stop the running Batch or wait until batch processing has finished. Select NFP Recovery on the Batch menu. The server attempts to write back all data that were temporarily stored to the local drive during the network failure to their proper locations on the network datasource. The network failure and the recovery are logged in the Audit Trail. (For more Audit Trail information, refer to Data Management  Audit Trails.)

As soon as the network connection is restored, Chromeleon automatically attempts to write the data back at the following time intervals:

• First, three times at 5-minute intervals.

• Then, three times at 15-minute intervals.

• Then, 24 times at 1-hour intervals.

• Finally, seven times at 24-hour intervals.

 Note: 

These attempts may occur during the daily network backup. If necessary, you can prevent this by specifying an appropriate period on the Availability tab page (see below).

 Tip: 

Automatic recovery (NFP Recovery) is enabled by default. If you want to disable this option, enter the following value (type DWORD) into the registry:

[HKEY_LOCAL_MACHINE\SOFTWARE\Dionex\Chromeleon\NetworkFailureProtection\Server]NoAutoRecovery

(Please note: If this key does not exist in your registry, generate it to disable automatic recovery.)

If the value does not exist or is set to 0, automatic recovery is enabled. For any other value, the option is disabled.

Select NFP Recovery on the Batch menu if:

• You have disabled automatic recovery in the registry.

• The network connection has been restored and you do not want to wait for the next automatic recovery attempt.

Network recovery sometimes fails due to problems with the ODBC driver or the network driver. In this case, restart the Chromeleon server after the batch finishes. To make sure that Windows and all other applications work properly, Dionex recommends rebooting the PC before you restart the Chromeleon server.

During Backup or Non-Availability of the Network Database

In many companies and organizations, the Datasource or Database is not available during the daily backup. However, you can easily ensure that Chromeleon is disconnected before the backup starts:

Click the datasource of interest and select Properties on the File or context menu. On the Availability tab page, enter the period during which the datasource will be unavailable, but specify a time interval that starts a few minutes before the backup actually begins.

If data is acquired while the network is not available, it will automatically be transferred to the network database as soon as the network is available again.

Limitations of Network Failure Protection (NFP)

Caution: Risk of Data Loss / Abort of Sequence

Network failure proctection (NFP) is not available for certain use cases. This may result in loss of data and/or aborted sequences, if the network is temporarily not available.

The following use cases are not supported by NFP:

• When recording absorbance spectra using the Scan command (for example, ScanBaseline, ScanEmission). The sequence will be aborted.

• Daily Audit Trails cannot be recorded in case of a network error and will be lost. It is therefore recommended to store daily Audit Trails locally and not directly on the network.

When performing a System Suitability Tests (SST), certain actions may also result in an aborted sequence:

1. If the QNT file cannot be read due to a network error, NFP mode will become active and the SST test will be stopped. If the SST contains a test case in which Fail Action is set to "Abort Batch", the batch will then be aborted at this point.

2. The QNT file can be read but an error occurs during execution of the SST. The error will be recorded in the Audit Trail and the sequence may be aborted, too.  

For information about how to create network datasources, refer to Setting up a Datasource:

 Creating a Network Datasource

 Saving Chromatography Data on the Network