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SnapSync of a Sybase Database Fails with Error 5.16.2.2 when Choosing "New full backup" Option

Issue

Running a SnapSync of a Sybase database with the "New full backup" option fails with an error similar to the following.

Run SnapSync for database "bucks".

Failed to dump the database "bucks" on instance "RH65_ASE16_S1" using backup server "RH65_ASE16_TGT_S1_BS": 501602: Backup Server: 5.16.2.2: Client-Library error: Error number 44, Layer 4, Origin 1, Severity 4: ct_connect(): protocol specific layer: external error: The attempt to connect to the server failed.

Make sure that the backup servers are configured correctly between the source instance "RH65_ASE16_S1" and the staging instance "RH65_ASE16_TGT_S1", and try the operation again.

Troubleshooting

The Sybase backup server error log on the staging host, /opt/sybase/errorlogs/RH65_ASE16_TGT_S1_BS.log, shows the reason for the failed connection attempt from the source host.

Aug  6 05:42:33 2016: Backup Server: 2.24.2.1: The host '10.43.43.196' is not authorized to connect to this Backup Server.
Aug  6 05:42:33 2016: Backup Server: 5.40.2.1: Login host authentication has failed.

Cause

Sybase ASE 15.7 SP50 introduced Remote Dump Host Control which provides the ability to restrict connections to the backup server to only specified hosts.

Resolution

Client hosts can be added via the Sybase hosts.allow file on the staging host. By default, it resides in $SYBASE but the current location is shown in the backup server log file during start-up, e.g.

Aug  6 01:25:19 2016: Backup Server: 1.88.1.1: The hosts authentication file used by the backup server is '/opt/sybase/16-0/hosts.allow'.

This file can be created if it does not already exist. The file contains entries of the following form, specifying the IP address or hostname of the system running the backupserver process and the client system that is attempting to connect.

<host_running_backup_server>    <host_trying_to_connect>