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Long filename support, introduced in OneFS 9.3, extends both the maximum length of a filename and the maximum length of a directory pathname from the previous limit of 255 bytes to new limits of 1,024 UTF-8 characters and/or 1,024-byte filenames. In concert with this increase in filename size, the maximum path length was quadrupled to 4,096 bytes from the current limit of 1,024 bytes.
OneFS domains govern filename length configuration. A domain defines a set of behaviors for a collection of files under a specified directory tree. Using domains allows for a uniform maximum length of a filename across all OneFS protocol heads and with a single configuration point per domain. The isi namelength list -v CLI command shows the backing domain ID on a particular directory. For example:
# isi namelength list -v
Path: /ifs/test
Policy: custom
Max Bytes: 1024
Max Chars: 1024
ID: 1e.0600