High Availability

This section describes known high-availability database (HADB) issues and associated solutions.

hadbm set Does Not Check Resource Availability (Disk and Memory Space) (ID 5091280)

When you increase the device or buffer sizes by using hadbm set, the management system checks resource availability when creating databases or adding nodes. However, the system does not check if sufficient resources are available when device or main-memory buffer sizes are changed.

Solution

Verify that enough free disk or memory space is available on all hosts before increasing any of the devicesize or buffersize configuration attributes.

Heterogeneous Paths for packagepath Not Supported (ID 5091349)

You cannot register the same software package with the same name with different locations at different hosts. For example:

hadbm registerpackage test --packagepath=/var/install1 --hosts europa11
Package successfully registered.
hadbm registerpackage test --packagepath=/var/install2 --hosts europa12
hadbm:Error 22171: A software package has already been registered with 
the package name test.

Solution

HADB does not support heterogeneous paths across nodes in a database cluster. Make sure that the HADB server installation directory (--packagepath) is the same across all participating hosts.

createdomain Might Fail (IDs 6173886, 6253132)

If running the management agent on a host with multiple network interfaces, the createdomain command might fail if not all network interfaces are on the same subnet:

hadbm:Error 22020: The management agents could not establish a 
domain, please check that the hosts can communicate with UDP multicast.

If not configured, the management agents will (use the "first" interface for UDP multicasts. "First" is defined by the result from java.net.NetworkInterface.getNetworkInterfaces().

Solution

The best solution is to tell the management agent which subnet to use (set ma.server.mainternal.interfaces in the configuration file. For example, ma.server.mainternal.interfaces=10.11.100.0). Alternatively you might configure the router between the subnets to route multicast packets (the management agent uses multicast address 228.8.8.8).

Before retrying with a new configuration of the management agents, you might have to clean up the management agent repository. Stop all agents in the domain, and delete all files and directories in the repository directory, identified by repository.dr.path in the management agent configuration file. This cleanup must be performed on all hosts before restarting the agents with a new configuration file.

Directories Must Be Cleaned Up After Deleting an HADB Instance (ID 6190878)

After deleting an HADB instance, subsequent attempts to create new instances with the configure-ha-cluster command fail. The problem is that old directories are left from the original HADB instance in ha_install_dir/rep/* and ha_install_dir/config/hadb/instance_name.

Solution

Be sure to manually delete these directories after deleting an HADB instance.

clu_trans_srv Cannot Be Interrupted (ID 6249685)

A bug in the 64-bit version of Red Hat Enterprise Linux 3.0 forces the clu_trans_srv process into an uninterruptible mode when performing asynchronous I/O. This means that kill -9 command does not work and the operating system must be rebooted.

Solution

Use a 32-bit version of Red Hat Enterprise Linux 3.0.

hadbm Does Not Support Passwords Containing Capital Letters (ID 6262824)

Capital letters in passwords are converted to lowercase when the password is stored in hadb.

Solution

Do not use passwords containing capital letters.

hadbm/ma Produces Faulty Error Message When a Session Object Times Out and Deletes at Management Agent (ID 6275103)

Sometimes a resource contention problem on the server may cause a management client to become disconnected. When reconnecting, the following misleading error message "hadbm:Error 22184: A password is required to connect to the management agent" might be returned.

Solution

Check if a resource problem has occurred on the server, take proper action (for example, , add more resources), and retry the operation.

The Management Agent Should Not Use Special-Use Interfaces. (ID 6293912)

Special-use interfaces with IP addresses like 0.0.0.0 should not be registered as valid interfaces to be used for HADB nodes in the Management Agent. Registering such interfaces can cause problems if HADB nodes are set up on these interfaces by means of a user issuing a hadbm create command that uses host names instead of IP addresses. The nodes will then be unable to communicate, causing the create command to hang.

Solution

When using hadbm create on hosts with multiple interfaces, always specify the IP addresses explicitly by using DDN notation.

Reassembly Failures on Windows (ID 6291562)

On the Windows platform, with certain configurations and loads, a large number of reassembly failures might occur in the operating system. The problem has been seen with configurations of more than 20 nodes when running several table scans (select *) in parallel. Possible symptoms include transactions aborting frequently, repair or recovery taking a long time to complete, and frequent timeouts occurring in various parts of the system.

Solution

To fix the problem, the Windows registry variable HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters can be set to a value higher than the default 100. For best results, increase this value to 0x1000 (4096). For more information, see article 811003 from the Microsoft support pages.

When Running hadbm start db_name, Part of Typed Password Displayed Without Being Masked (IDs 6303581, 6346059, 6307497)

When a machine is overloaded, the masking mechanism fails and some characters from the typed password can be exposed. This exposition poses a minor security risk. The password should always be masked.

Solution

Put the passwords in their own password files (the method recommended since Application Server 8.1) and refer to these files with either the --adminpassword or --dbpasswordfile options.