- The repository shall actively monitor the integrity of AIPs.


SP is committed to maintaining the integrity of objects in its care. This includes regular fixity checking of all accepted and ingested files.

  • At the time of ingest, three checksum values are calculated for each file: MD5, SHA-1, and CRC32. These values are stored in the preservation metadata for each object.
  • Nightly, a set number of  files in the repository will have their current checksum calculated (using a single checksum) and compared to this stored value, which is expected to match. In cases where the calculated and stored values do not match, this is reported to Scholars Portal's issue tracking system, JIRA.

PREMIS events are created in the preservation metadata at the object-level for the fixity checks and success or failure of these checks are logged.

Please see Fixity Check Procedures for more details.

The Content Information is stored on disk, and the fixity information is stored in the TDR database.


Digital Preservation Policy Librarian

Relevant Documents

  1. Fixity Check Procedures
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