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Sun QFS and Sun Storage Archive Manager 5.3 Reference Manual Sun QFS and Sun Storage Archive Manager 5.3 Information Library |
1. User Commands (Man Pages Section 1)
2. Maintenance Commands (Man Pages Section 1M)
3. Library Functions (Man Pages Section 3)
4. Library Functions (Man Pages Section 3X)
5. File Formats (Man Pages Section 4)
NAME ssum - Set file checksum attributes SYNOPSIS ssum [-d] [-e] [-f] [-g] [-u] filename... ssum [-d] [-e] [-f] [-g] [-u] -r dirname...[filename...] AVAILABILITY SUNWsamfs DESCRIPTION ssum sets the checksum attributes on one or more files. If the generate attribute is set (-g), a 128-bit value is gen- erated when the file is archived. When the file is subse- quently staged, the checksum is again generated and is com- pared against the value generated at archive time if the use attribute is set (-u). By default, no checksum value is generated or used when archiving or staging a file. The generate attribute must be set on a file before any archive copy has been made. Likewise, the selected algo- rithm cannot be changed after an archive copy has been made. Direct access (stage -n) and partial release (release -p) are not allowed on a file that has the checksum use attri- bute set. Also, it is not valid to specify that a file never be archived (archive -n) as well as specify that a checksum be used. Therefore, when a direct access, partial release, or archive never attribute is set on a file, attempting to set the checksum generate or use attribute on the file will result in an error and the attributes will be unchanged. Similarly, when either the checksum generate or use attri- bute is set on a file, attempting to set a direct access, partial release, or archive never attribute on the file will result in an error and the attributes will be unchanged. A file that has the checksum use attribute set cannot be memory mapped. The file also must be completely staged to the disk before access is allowed to the file's data. This means that accessing the first byte of offline data in an archived file that has this attribute set will be slower than accessing the same archived file when it does not have this attribute set. This also means that staging will operate the same way as for staging with the -w option for a file with the use attribute not set. OPTIONS -d Return the file's checksum attributes to the default, which turns off checksumming. Using the -d option will not reset the 'checksum valid' flag if a valid checksum has been generated for a file. The -d option deletes the checksum attributes, if no valid checksum has been generated. -e Set data verification for the file or directory speci- fied. This forces the generation and use of checksums for archiving and staging, and prevents the release of the file until all archive copies have been created and their checksums verified. A file with only one archive copy will never be released. Only a superuser can set this attribute on a file. Files created in directories with the -e flag set inherit it. -f Do not report errors. -r Recursively set the attributes for any files contained in the specified dirname and its subdirectories. -g Generate a checksum value for the file when archiving. -u Use the checksum value for the file when staging. The generate attribute must have been previously set, or must be set simultaneously. SEE ALSO stage(1), release(1), archive(1), sls(1)