User guide

B
Cache check tools
reference
IMPAX 6.4 includes four tools designed to ensure the integrity of the IMPAX cache directory. These
tools check the cache directory, repair the cache directory, and then provide a 'Loss Report' for files
missing from the cache.
mvf-check-cache
This command checks that all the DICOM object files registered in the database for a particular cache
volume actually exists in the cache. It also does a sanity check to determine whether the files are correct
by comparing the sop_instance_uid to the value in the database. A report giving precise details of the
problems found is produced and written to the log file. Optionally, a move-cmds.sh file is created to
move the problematic files out of the cache. Files in the cache that do not have locations registered in
the database are not detected by mvf-check-cache.
If there are multiple caches, the path name of the cache to be checked must be specified. Memory usage
may be high if there are a large number of files, but mvf-check-cache displays the amount of memory
required so that the operator can add more virtual memory if needed
Performance of mvf-check-cache is hardware dependant. For example, on a Sunfire 280R,
mvf-check-cache can check about 130 files per second. With the quick check option enabled (checking
only file existence and file size), about 30,000 files per second can be checked.
mvf-clean-cache
This command scans an IMPAX cache directory containing DICOM object files and generates a report
of files that do not belong there, either because the file name format is invalid or because this location
for the object file is not registered in the database. While working, it writes messages to the stderr
stream to keep the tool operator informed of its progress. The path name of the cache to be scanned is
specified on the command line. mvf-clean-cache begins by querying the database for the list of ordinals
for the files in the cache. It keeps this list in memory. If there is a large number of files, memory usage
AS300 Upgrade Guide—IMPAX 6.2 or later to IMPAX 6.4 69
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