Data Verification

You can enable data verification for archive copies. This feature checks for data corruption on any data that is copied to secondary and/or tertiary media.

The data verification process performs a read-after-write verification test and records a confirmation of data validity in the metadata properties for that file. The process uses the ssum option to mark files and directories to be verified. The normal checksum method is employed to verify copies written to tape or disk archive.

Use the ssum -e command to set data verification for a file or directory. A child directory inherits the data verification properties of its parent. This command forces the generation and use of checksums for archiving and staging. It also prevents the release of the file until all archive copies have been created and their checksums verified. Only superuser can set this attribute on a file or directory.

Note - Data verification places an additional burden on stager resources because data verification requests are placed on the stager queue in addition to normal stage requests. Data verification also leads to additional tape mounts and therefore affects archiver and stager performance. Because a file cannot be released until all archive copies are made, using data verification might also require additional disk cache.

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	Sun Storage Archive Manager 5.3 Configuration and Administration Guide Sun QFS and Sun Storage Archive Manager 5.3 Information Library