For details about configuring the cache directory structure, refer to Configuring the hierarchical cache directory structure.
Before starting the migration, verify the condition of the caches:
Install the MVFcachecheck package.
Run the mvf-clean-cache tool.
If the mvf-clean-cache output indicates that there are problems, resolve them.
IMPAX stores DICOM objects in cache so that they can be displayed, transmitted to other DICOM devices, and archived. Prior to IMPAX 6.5, the cache structure was flat (each cache volume contained one directory), which limited the cache size because once a certain number of objects are in the directory, access to the cache can become very slow. Large sites may resolve this by deploying numerous cache volumes, which can be difficult to manage.
As of IMPAX 6.5, a hierarchical cache structure is supported for image and web caches, permitting larger cache volumes. The old flat cache structure continues to be supported; only new images arriving in the system or existing images retrieved from archive are written to cache using the hierarchical structure. However, the cache migration tool allows a site to migrate its existing caches if it would like to immediately take advantage of the hierarchical structure.
 | Note: The cache migration tool is included in the MVFCache (Windows) and IMPAXmvfc (Solaris) packages, which are part of the standard IMPAX install packages. |
To migrate a cache volume from a flat to a hierarchical structure
At a command prompt on the system where the cache volume is local, type
cache_migration.exe parameters (Windows)
or
cache-migration parameters (Solaris, logged in as mvf user)
where parameters are as follows:
Parameters Values Default value -S The cache volume to migrate from. If a source_volume_ref is not specified, you are prompted to choose from a list. If the destination volume is different from the source volume, make sure that the source cache volume is closed before running the cache-migration tool. When closed, new images cannot be received by this volume, which will likely be removed after the migration. To close the cache volume, start the CLUI tool and type
cache close volume_refNot applicable -D The cache volume to migrate to. It can be the same as the source volume. There should be enough space in the destination volume for all the studies in the source volume. If a destination_volume_ref is not specified, you are prompted to choose from a list. Not applicable -X number—The delay in seconds before the original files are deleted. If not specified, the original files are not deleted. If 0, the original files are deleted immediately. Not applicable -F number—The maximum number of cache files to be handled by each thread in the application; a performance-tuning parameter. 100-T number—The number of threads to handle the copying of files; a performance-tuning parameter. 3-I number—How often to report on the progress of the migration, in minutes. 5-f log_file—Log file name. Not applicable 
Tip:
Use the -? parameter to view usage or help information.
Example:
cache_migration.exe -F 500 -T 4 -I 2 -f migration.log List of eligible cache volumes 1000 : /cache/mvfcache 1001 : /cache/vcacheRSNA2003 1002 : /cache/newcache Source volume_ref? 1000 Destination volume_ref? 1000 Delete original files (Y/N)? y How long to wait to delete (sec)? 10
After the migration, verify the condition of the caches:
Run the mvf-clean-cache tool.
If the mvf-clean-cache output indicates that there are problems, resolve them.