The '8.3'-Fgn Pattern; Best Practice: Avoid Primary Names That Match This Pattern - Acopia Adaptive Resource Switch Cli Maintenance Manual

Troubleshooting Managed Volumes
Finding Collisions with CIFS '8.3' Names

The '8.3'-FGN Pattern

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Filers generate alternate 8.3 names with specific patterns, usually including a tilde (~)
character to indicate that the name is filer-generated. Any 8.3 FGN falls into one of
two patterns:
name-with-tilde[.ext]
is the most-common pattern, where
• name-with-tilde (2-8 characters) has one tilde (~) character (such as
"RANDOM~2"), and
• ext is optional and has 1-3 characters.
name-without-tilde[.ext]
is a pattern that EMC file servers use in some cases, where
• name-without-tilde (exactly 8 characters) has no tilde (~) character (such as
"0000D773"), and
• ext is optional and has 1-3 characters.
Clients should avoid any primary names that match these patterns. They incur a slight
performance penalty, and in rare cases the volume may disallow certain client actions
or policy actions for them.

Best Practice: Avoid Primary Names that Match this Pattern

Whenever a file or directory matches the 8.3-FGN pattern above, certain operations
on the entry require additional processing. An operation triggers the extra processing
only if it requires the volume to migrate or replicate one of these entries between
shares. Such an operation is uncommon. The volume's additional processing is a
query to the back-end share(s), searching for an alternate name that matches the
offending primary name. If the volume finds a collision, it disallows the operation.
For directory names that match the 8.3-FGN pattern, some cross-share operations
inside the directory can trigger the processing. That is, some operations on its
descendant files or directories may require extra back-end queries. These
circumstances are rare, but have a performance penalty.
Wherever practical, clients should avoid these naming patterns.
CLI Maintenance Guide