Chapter 6. Server Failure

Table of Contents

6.1. Abnormal Termination of Domain Administration Server (DAS)
6.1.1. Lost Functionality if DAS Terminates Abnormally
6.1.2. Failover
6.1.3. Managed Servers(MSs) in INDEPENDENT Mode
6.2. Abnormal Termination

Abnormal termination of a server that causes service issues can occur for many reasons. These issues can be minimized by creating clusters. This chapter describes the issues that may occur if a server terminates abnormally and how to handle them.

Even if DAS terminates abnormally, managed servers(MS) can still run their services. If DAS stops abnormally due to a hardware error, MSs on the faulty machine are likely to fail as well. However, abnormal termination of DAS itself does not affect the services of MSs in the domain.

Even if DAS terminates abnormally, the services can still run but some functions cannot be used. DAS should be restarted as soon as possible, but there are situations where DAS cannot restart due to such problems as a hardware failure.

To prepare for this, DAS settings and applications should be backed up. DAS can start on another machine by copying previously backed up DAS files to that machine.

The following are the methods for backing up and restoring DAS settings and applications.

Once DAS starts with the recovered settings, MSs that were in the INDEPENDENT mode synchronize their settings and applications with DAS. Afterwards, they leave the INDEPENDENT mode and are managed by DAS again.

Note

Refer to JEUS Reference Book. "4.2.4.28. pack-domain", JEUS Reference Book. "4.2.4.30. unpack-domain", and JEUS Reference Book. "4.2.4.29. set-domain-backup" for detailed information about the pack-domain, unpack-domain, and set-domain commands respectively.

Managed servers in a domain can detect the abnormal termination of another server because they exchange state information through multicast. If the server is configured to automatically restart, DAS will automatically restart the server.