World Community Grid - View Thread - Restoring (Re)Install Clients & How to Avoid New Registrations without Merge functionality

There are a number of reasons why new devices are being created, obviously a new computer, new harddisk, doing a clean install or problems with security software causing the WCG servers not to recognize the connecting client.

Absent Host Merge Functionality there are several ways to achieve a reuse of a previously existing host/device, the most important item to know that it only works on a 1 for 1 basis. There cannot be the same client ID installed on multiple *project connecting* computers without the risk of the servers identifying the device as new and or seeing conflict and deeming the work already downloaded belonging to an different device.

Important: Before continuing, read the whole document before starting so you understand all the caveats.

Prerequisites for Accomplishment:

A good back-up of an existing device install is on hand of the BOINC Client installation, the programs and the data directory structure. Critical files are
- client_state.xml
- account_worldcommunitygrid.org.xml
- global_prefs.xml and global_prefs_override.xml
- master_www.worldcommunitygrid.org.xml
- sched_reply_www.worldcommunitygrid.org.xml
- sched_request_www.worldcommunitygrid.org.xml
- statistics_www.worldcommunitygrid.org.xml
- all files in the ..\projects\www.worldcommunitygrid.org
which need to be in proper state and of the same backup point.
The hardware and operating system are of the same family... Linux for Linux, Windows for Windows etc.

When re-imaging or clean installing or moving to a new computer, retire the old computer from WCG participation.

Actions to Reuse a device:

Take backup point 1. above and restore to the new computer, to a directory of choice, ideally the same relative location as on the old install.
Install the client software, while *Off-line/Disconnected from Internet*, as were it a new client to the to same place as where the old client was and point installer to the correct data directory if not automatically selected correctly. **
Start client/agent as was normally done.

Just having practiced this with a brand new, super fast disk, it worked a dream and continued where it left off on the old disk.

** Some have manually split the BOINC program and Data directories which happens automatically from future BOINC version 6. For Windows, the BOINC client would be default installed to C:\Program Files\BOINC\ and the data to C:\ProgramData\BOINC\. Given the data for each main project is stored in a subdirectory structure, the one this project would be C:\ProgramData\BOINC\projects\www.worldcommunitygrid.org

Regarding BOINC, these instructions work for either single/shared/service. The steps A/B ensure the OS is aware of the software presence and normal un-install can be performed as applicable to the respective Operating Systems.

Merging devices as long standing wish list item and with migrating all WCG projects exclusively to BOINC, this is until then a way to avoid additional devices.

Alternate identification method at World Community Grid

In absence of a merge feature at this BOINC project, WCG introduced an alternate method called host matching to recognize previously existing devices to prevent new / duplicate registrations. For that the server compares standard information exchanged during server-client communications being:

user name (network name of host e.g. "MY1STCOMPUTER")
domain_name (default for Windows is "WORKGROUP")
ip_addr (the ip of the client on the local network)
operating system name
processor vendor
memory

The most recent record that matches this criteria (if found) will be re-used. If the restore is from a backup not immediately done before, BOINC will cancel any results currently assigned to the client, and then issue new work. This is because a user might be trying to clear out some work that was causing some form of trouble. If any of this information is hidden through for instance setting the <suppress_net_info> flag in the cc_config.xml file hiding the LAN IP address or domain_name, the method fails and will create a new device/host registration.

~~

Related Topics:

Return to the Start Here FAQ index