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From time to time the registry server host may become unavailable; you then need to designate a new registry server. At that time, you may or may not have a backup host prepared to become the new registry server. This section uses two examples of these conditions:
You have a functioning backup registry host, on which rgy_backup has been running at regular intervals.
No designated backup registry host is available.
In both cases, the rgy_switchover utility does the key work.
In this scenario, primary registry host rgy1 fails, and the ClearCase administrator makes backup registry host rgy2 the new primary server. (rgy_backup has been executing successfully on rgy2.) While rgy1 is down and rgy2 is the primary registry server, rgy3 becomes the backup registry server. Later, rgy1 becomes available again, and the administrator reverts to rgy1 as the primary registry server.
Use this procedure to switch the registry server. You must have write permission to the directory ccase_var_dir\rgy to run rgy_backup.
Run rgy_switchover. Make rgy2 the primary registry server. Make rgy3 the new backup registry server:
rgy_switchover -backup rgy3 rgy1 rgy2
Handle unreachable clients. Record the names of any client hosts for which the switchover fails. You will reset these hosts by hand (or have their owners do so) when they become available. Later, when a failed client becomes available, take the following steps:
Log on to the client.
Configure the client to use the new registry host. On UNIX clients, set the first line of its rgy_hosts.conf file to rgy2. On Windows clients, use the Registry tab of the ClearCase program in Control Panel. Click Use registry server on host. In the Use registry server on host box, enter rgy2. On the Registry tab, enter rgy3 in the Backup registry host box. Click OK or Apply.
Stop ClearCase.
Restart ClearCase.
NOTE. ClearCase hosts with client-only installations and ClearCase Attache clients cannot be reconfigured by rgy_switchover and always appear on the list of unreachable clients.
Because registry contents can change frequently as VOB-tags and view-tags are created and deleted, you cannot simply restart a failed registry host after a period of using a backup registry host. Use this procedure if you have switched to a backup registry server (rgy2 in our example) and want to switch back to using the primary registry server rgy1. You must have write permission to the directory ccase_var_dir\rgy to run rgy_backup.
Host rgy1 becomes available again.
Deactivate rgy1. rgy1 is still configured as a registry host. Reconfigure it to recognize rgy2 as the registry host. Then make rgy1 a backup registry host, so that it takes a registry snapshot in preparation for returning to its role as primary registry server:
Log on to rgy1.
Reconfigure rgy1 as a backup registry server. On UNIX, edit rgy_svr.conf to remove the string master, then edit rgy_hosts.conf to change its first line to rgy2 and its second line to rgy1. On Windows Control Panel, click the Registry tab of the ClearCase program. Click Use registry server on host. Enter rgy2 in the Use registry server on host box. On the Registry tab, enter rgy1 in the Backup registry host box. Click OK or Apply.
Stop ClearCase.
Restart ClearCase.
Copy the active registry files to rgy1. Run rgy_backup manually on rgy1, forcing it to take a snapshot of the active registry files on rgy2, in preparation for returning rgy1 to service as the primary registry server. On rgy1, run rgy_backup
Run rgy_switchover. Make rgy1 the primary registry server host. Return rgy2 to its former role as the backup registry host with the following command:
rgy_switchover -backup rgy2 rgy2 rgy1
Handle unreachable clients. Any rgy_switchover operation is likely to require this step. See Step #2 here for details.
In this scenario, either your site has failed to configure or maintain a backup registry host, or the backup registry host has failed along with the primary registry host. You want to move the ClearCase registry from host rgy1 to host rgy2. When you do so, the primary registry host, rgy1, may or may not be available. The procedures presented here handle both cases.
You must have write permission to the directory ccase-var-dir\rgy to run rgy_backup.
Configure rgy2 as a backup registry host. Follow the procedure in Changing Backup Registry Host Without rgy_switchover.
Copy the registry files to rgy2. Run rgy_backup on rgy2:
rgy_backup
Primary host rgy1 is unavailable; prospective registry host rgy2 is not configured as a backup registry host. You must restore the rgy directory backup from rgy1 to the rgy directory tree on rgy2 and reconfigure all hosts.
The following procedure is a potentially time-saving alternative, in which you restore and re-create registry-related files on the target registry host, rgy2, making it possible to run rgy_switchover as if rgy2 were a real backup registry host.
Restore registry files to target registry host, rgy2, from backup. Retrieve the ClearCase rgy directory and client_list.db file from backup and load its files into ccase-var-dir/rgy/backup. When you are finished, the backup subdirectory includes all the registry data files listed in the rgy_backup reference page.
Look for the client_list.db file. A registry host stores its client_list.db file alongside (not in) the rgy directory in ccase-var-dir. If you do not have this file, rgy_switchover cannot reconfigure clients for you. You must do it by hand by editing the rgy_hosts.conf file on UNIX clients or, on Windows, running Control Panel and using the Registry tab of the ClearCase program.
Create a backup_list file. Create a text file named backup_list and put it into the backup directory. The first line of backup_list must be the name of the primary registry server, in this case rgy1. The remaining lines of backup_list must be the names of all the registry data files listed in the rgy_backup reference page, one file name per line. List only the name of each file, not the path to the file.
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