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Terminology
|
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</span>
|
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|
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</a>
|
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</li>
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<li class="md-nav__item">
|
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<a href="../../config/options/" class="md-nav__link">
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<span class="md-ellipsis">
|
|
Options
|
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</span>
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</a>
|
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</li>
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<li class="md-nav__item">
|
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<a href="../../config/deprecated_options/" class="md-nav__link">
|
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|
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<span class="md-ellipsis">
|
|
Deprecated Options
|
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</span>
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</a>
|
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</li>
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<li class="md-nav__item">
|
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<a href="../../config/branches/" class="md-nav__link">
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|
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<span class="md-ellipsis">
|
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branches
|
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</span>
|
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</a>
|
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</li>
|
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<li class="md-nav__item">
|
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<a href="../../config/functions_categories_and_policies/" class="md-nav__link">
|
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|
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<span class="md-ellipsis">
|
|
functions, categories and policies
|
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</span>
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</a>
|
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</li>
|
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<li class="md-nav__item">
|
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<a href="../../config/func_readdir/" class="md-nav__link">
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|
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<span class="md-ellipsis">
|
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func.readdir
|
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</span>
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</a>
|
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</li>
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<li class="md-nav__item">
|
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<a href="../../config/rename_and_link/" class="md-nav__link">
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|
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<span class="md-ellipsis">
|
|
rename and link
|
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</span>
|
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|
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</a>
|
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</li>
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<li class="md-nav__item">
|
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<a href="../../config/cache/" class="md-nav__link">
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|
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<span class="md-ellipsis">
|
|
caching
|
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</span>
|
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</a>
|
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</li>
|
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<li class="md-nav__item">
|
|
<a href="../../config/readahead/" class="md-nav__link">
|
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|
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|
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<span class="md-ellipsis">
|
|
readahead
|
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</span>
|
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</a>
|
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</li>
|
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<li class="md-nav__item">
|
|
<a href="../../config/inodecalc/" class="md-nav__link">
|
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|
|
|
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<span class="md-ellipsis">
|
|
inodecalc
|
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</span>
|
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|
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</a>
|
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</li>
|
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|
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<li class="md-nav__item">
|
|
<a href="../../config/threads/" class="md-nav__link">
|
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|
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|
|
<span class="md-ellipsis">
|
|
threads
|
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</span>
|
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|
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</a>
|
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</li>
|
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|
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<li class="md-nav__item">
|
|
<a href="../../config/pin-threads/" class="md-nav__link">
|
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|
|
|
|
<span class="md-ellipsis">
|
|
pin-threads
|
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</span>
|
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|
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</a>
|
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</li>
|
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|
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<li class="md-nav__item">
|
|
<a href="../../config/link_cow/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
link_cow
|
|
</span>
|
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|
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</a>
|
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</li>
|
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|
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<li class="md-nav__item">
|
|
<a href="../../config/fuse_msg_size/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
fuse_msg_size
|
|
</span>
|
|
|
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|
|
</a>
|
|
</li>
|
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|
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<li class="md-nav__item">
|
|
<a href="../../config/follow-symlinks/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
follow-symlinks
|
|
</span>
|
|
|
|
|
|
</a>
|
|
</li>
|
|
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|
|
<li class="md-nav__item">
|
|
<a href="../../config/link-exdev/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
link-exdev
|
|
</span>
|
|
|
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|
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</a>
|
|
</li>
|
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|
|
<li class="md-nav__item">
|
|
<a href="../../config/rename-exdev/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
rename-exdev
|
|
</span>
|
|
|
|
|
|
</a>
|
|
</li>
|
|
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|
|
<li class="md-nav__item">
|
|
<a href="../../config/symlinkify/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
symlinkify
|
|
</span>
|
|
|
|
|
|
</a>
|
|
</li>
|
|
|
|
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|
|
<li class="md-nav__item">
|
|
<a href="../../config/nullrw/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
nullrw
|
|
</span>
|
|
|
|
|
|
</a>
|
|
</li>
|
|
|
|
|
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|
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|
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|
|
<li class="md-nav__item">
|
|
<a href="../../config/xattr/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
xattr
|
|
</span>
|
|
|
|
|
|
</a>
|
|
</li>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
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|
|
<li class="md-nav__item">
|
|
<a href="../../config/nfsopenhack/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
nfsopenhack
|
|
</span>
|
|
|
|
|
|
</a>
|
|
</li>
|
|
|
|
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|
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|
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|
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|
|
|
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|
|
<li class="md-nav__item">
|
|
<a href="../../config/statfs/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
statfs / statvfs
|
|
</span>
|
|
|
|
|
|
</a>
|
|
</li>
|
|
|
|
|
|
|
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|
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|
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|
|
<li class="md-nav__item">
|
|
<a href="../../config/flush-on-close/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
flush-on-close
|
|
</span>
|
|
|
|
|
|
</a>
|
|
</li>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
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|
|
|
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|
|
<li class="md-nav__item">
|
|
<a href="../../config/export-support/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
export-support
|
|
</span>
|
|
|
|
|
|
</a>
|
|
</li>
|
|
|
|
|
|
|
|
|
|
</ul>
|
|
</nav>
|
|
|
|
</li>
|
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|
|
<li class="md-nav__item">
|
|
<a href="../../error_handling/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
Error Handling
|
|
</span>
|
|
|
|
|
|
</a>
|
|
</li>
|
|
|
|
|
|
|
|
|
|
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|
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|
|
<li class="md-nav__item">
|
|
<a href="../../runtime_interfaces/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
Runtime Interfaces
|
|
</span>
|
|
|
|
|
|
</a>
|
|
</li>
|
|
|
|
|
|
|
|
|
|
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|
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|
|
<li class="md-nav__item">
|
|
<a href="../../remote_filesystems/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
Remote Filesystems
|
|
</span>
|
|
|
|
|
|
</a>
|
|
</li>
|
|
|
|
|
|
|
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|
|
<li class="md-nav__item">
|
|
<a href="../../tips_notes/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
Tips and Notes
|
|
</span>
|
|
|
|
|
|
</a>
|
|
</li>
|
|
|
|
|
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|
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|
|
<li class="md-nav__item">
|
|
<a href="../../known_issues_bugs/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
Known Issues and Bugs
|
|
</span>
|
|
|
|
|
|
</a>
|
|
</li>
|
|
|
|
|
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|
|
<li class="md-nav__item">
|
|
<a href="../../project_comparisons/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
Project Comparisons
|
|
</span>
|
|
|
|
|
|
</a>
|
|
</li>
|
|
|
|
|
|
|
|
|
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|
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|
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|
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|
|
<li class="md-nav__item">
|
|
<a href="../../performance/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
Tweaking Performance
|
|
</span>
|
|
|
|
|
|
</a>
|
|
</li>
|
|
|
|
|
|
|
|
|
|
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|
|
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|
|
<li class="md-nav__item">
|
|
<a href="../../benchmarking/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
Benchmarking
|
|
</span>
|
|
|
|
|
|
</a>
|
|
</li>
|
|
|
|
|
|
|
|
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|
|
<li class="md-nav__item">
|
|
<a href="../../tooling/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
Tooling
|
|
</span>
|
|
|
|
|
|
</a>
|
|
</li>
|
|
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|
|
<li class="md-nav__item md-nav__item--active md-nav__item--nested">
|
|
|
|
|
|
|
|
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_14" checked>
|
|
|
|
|
|
<label class="md-nav__link" for="__nav_14" id="__nav_14_label" tabindex="0">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
FAQ
|
|
</span>
|
|
|
|
|
|
<span class="md-nav__icon md-icon"></span>
|
|
</label>
|
|
|
|
<nav class="md-nav" data-md-level="1" aria-labelledby="__nav_14_label" aria-expanded="true">
|
|
<label class="md-nav__title" for="__nav_14">
|
|
<span class="md-nav__icon md-icon"></span>
|
|
FAQ
|
|
</label>
|
|
<ul class="md-nav__list" data-md-scrollfix>
|
|
|
|
|
|
|
|
|
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|
|
|
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|
|
<li class="md-nav__item">
|
|
<a href="../reliability_and_scalability/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
Reliability and Scalability
|
|
</span>
|
|
|
|
|
|
</a>
|
|
</li>
|
|
|
|
|
|
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|
|
|
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|
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|
|
|
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|
|
<li class="md-nav__item">
|
|
<a href="../usage_and_functionality/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
Usage and Functionality
|
|
</span>
|
|
|
|
|
|
</a>
|
|
</li>
|
|
|
|
|
|
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|
|
<li class="md-nav__item">
|
|
<a href="../configuration_and_policies/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
Configuration and Policies
|
|
</span>
|
|
|
|
|
|
</a>
|
|
</li>
|
|
|
|
|
|
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|
|
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|
|
<li class="md-nav__item">
|
|
<a href="../compatibility_and_integration/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
Compatibility and Integration
|
|
</span>
|
|
|
|
|
|
</a>
|
|
</li>
|
|
|
|
|
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|
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|
|
<li class="md-nav__item">
|
|
<a href="../recommendations_and_warnings/" class="md-nav__link">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
Recommendations and Warnings
|
|
</span>
|
|
|
|
|
|
</a>
|
|
</li>
|
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|
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<li class="md-nav__item md-nav__item--active">
|
|
|
|
<input class="md-nav__toggle md-toggle" type="checkbox" id="__toc">
|
|
|
|
|
|
|
|
|
|
|
|
<label class="md-nav__link md-nav__link--active" for="__toc">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
Technical Behavior and Limitations
|
|
</span>
|
|
|
|
|
|
<span class="md-nav__icon md-icon"></span>
|
|
</label>
|
|
|
|
<a href="./" class="md-nav__link md-nav__link--active">
|
|
|
|
|
|
<span class="md-ellipsis">
|
|
Technical Behavior and Limitations
|
|
</span>
|
|
|
|
|
|
</a>
|
|
|
|
|
|
|
|
<nav class="md-nav md-nav--secondary" aria-label="Table of contents">
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<label class="md-nav__title" for="__toc">
|
|
<span class="md-nav__icon md-icon"></span>
|
|
Table of contents
|
|
</label>
|
|
<ul class="md-nav__list" data-md-component="toc" data-md-scrollfix>
|
|
|
|
<li class="md-nav__item">
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Table of contents
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Do hardlinks work?
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<span class="md-ellipsis">
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How does mergerfs handle moving and copying of files?
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Does FICLONE or FICLONERANGE work?
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</a>
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</li>
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<span class="md-ellipsis">
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Why do I get an "out of space" / "no space left on device" / ENOSPC error even though there appears to be lots of space available?
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</span>
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</a>
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</li>
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<span class="md-ellipsis">
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Why does the total available space in mergerfs not equal outside?
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</span>
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</a>
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</li>
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<li class="md-nav__item">
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<a href="#i-notice-massive-slowdowns-of-writes-when-enabling-cachefiles" class="md-nav__link">
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<span class="md-ellipsis">
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I notice massive slowdowns of writes when enabling cache.files.
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</span>
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</a>
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</li>
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<a href="#why-cant-i-see-my-files-directories" class="md-nav__link">
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<span class="md-ellipsis">
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Why can't I see my files / directories?
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</a>
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</li>
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Why use FUSE? Why not a kernel based solution?
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<a href="#is-my-oss-libfuse-needed-for-mergerfs-to-work" class="md-nav__link">
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Is my OS's libfuse needed for mergerfs to work?
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</span>
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</a>
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<a href="#why-was-splice-support-removed" class="md-nav__link">
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<span class="md-ellipsis">
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Why was splice support removed?
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<article class="md-content__inner md-typeset">
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<a href="https://github.com/trapexit/mergerfs/tree/master/mkdocs/docs/faq/technical_behavior_and_limitations.md" title="Edit this page" class="md-content__button md-icon">
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<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M10 20H6V4h7v5h5v3.1l2-2V8l-6-6H6c-1.1 0-2 .9-2 2v16c0 1.1.9 2 2 2h4zm10.2-7c.1 0 .3.1.4.2l1.3 1.3c.2.2.2.6 0 .8l-1 1-2.1-2.1 1-1c.1-.1.2-.2.4-.2m0 3.9L14.1 23H12v-2.1l6.1-6.1z"/></svg>
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<h1 id="technical-behavior-and-limitations">Technical Behavior and Limitations</h1>
|
|
<h2 id="do-hardlinks-work">Do hardlinks work?</h2>
|
|
<p>Yes. See also the option <code>inodecalc</code> for how inode values are
|
|
calculated.</p>
|
|
<p>What mergerfs does not do is fake hard links across branches. Read
|
|
the section "rename & link" for how it works.</p>
|
|
<p>Remember that hardlinks will NOT work across devices. That includes
|
|
between the original filesystem and a mergerfs pool, between two
|
|
separate pools of the same underlying filesystems, or bind mounts of
|
|
paths within the mergerfs pool. The latter is common when using Docker
|
|
or Podman. Multiple volumes (bind mounts) to the same underlying
|
|
filesystem are considered different devices. There is no way to link
|
|
between them. You should mount in the highest directory in the
|
|
mergerfs pool that includes all the paths you need if you want links
|
|
to work.</p>
|
|
<h2 id="how-does-mergerfs-handle-moving-and-copying-of-files">How does mergerfs handle moving and copying of files?</h2>
|
|
<p>This is a <em>very</em> common mistaken assumption regarding how filesystems
|
|
work. There is no such thing as "move" or "copy." These concepts are
|
|
high level behaviors made up of numerous independent steps and <em>not</em>
|
|
individual filesystem functions.</p>
|
|
<p>A "move" can include a "copy" so lets describe copy first.</p>
|
|
<p>When an application copies a file from source to destination it can do
|
|
so in a number of ways but the basics are the following.</p>
|
|
<ol>
|
|
<li><code>open</code> the source file.</li>
|
|
<li><code>create</code> the destination file.</li>
|
|
<li><code>read</code> a chunk of data from source and <code>write</code> to
|
|
destination. Continue till it runs out of data to copy.</li>
|
|
<li>Copy file metadata (<code>stat</code>) such as ownership (<code>chown</code>),
|
|
permissions (<code>chmod</code>), timestamps (<code>utimes</code>), extended attributes
|
|
(<code>getxattr</code>, <code>setxattr</code>), etc.</li>
|
|
<li><code>close</code> source and destination files.</li>
|
|
</ol>
|
|
<p>"move" is typically a <code>rename(src,dst)</code> and if that errors with
|
|
<code>EXDEV</code> (meaning the source and destination are on different
|
|
filesystems) the application will "copy" the file as described above
|
|
and then it removes (<code>unlink</code>) the source.</p>
|
|
<p>The <code>rename(src,dst)</code>, <code>open(src)</code>, <code>create(dst)</code>, data copying,
|
|
metadata copying, <code>unlink(src)</code>, etc. are entirely distinct and
|
|
separate events. There is really no practical way to know that what is
|
|
ultimately occurring is the "copying" of a file or what the source
|
|
file would be. Since the source is not known there is no way to know
|
|
how large a created file is destined to become. This is why it is
|
|
impossible for mergerfs to choose the branch for a <code>create</code> based on
|
|
file size. The only context provided when a file is created, besides
|
|
the name, is the permissions, if it is to be read and/or written, and
|
|
some low level settings for the operating system.</p>
|
|
<p>All of this means that mergerfs can not make decisions when a file is
|
|
created based on file size or the source of the data. That information
|
|
is simply not available. At best mergerfs could respond to files
|
|
reaching a certain size when writing data or when a file is closed.</p>
|
|
<p>Related: if a user wished to have mergerfs perform certain activities
|
|
based on the name of a file it is common and even best practice for a
|
|
program to write to a temporary file first and then rename to its
|
|
final destination. That temporary file name will typically be random
|
|
and have no indication of the type of file being written.</p>
|
|
<h2 id="does-ficlone-or-ficlonerange-work">Does FICLONE or FICLONERANGE work?</h2>
|
|
<p>Unfortunately not. FUSE, the technology mergerfs is based on, does not
|
|
support the <code>clone_file_range</code> feature needed for it to work. mergerfs
|
|
won't even know such a request is made. The kernel will simply return
|
|
an error back to the application making the request.</p>
|
|
<p>Should FUSE gain the ability mergerfs will be updated to support it.</p>
|
|
<h2 id="why-do-i-get-an-out-of-space-no-space-left-on-device-enospc-error-even-though-there-appears-to-be-lots-of-space-available">Why do I get an "out of space" / "no space left on device" / ENOSPC error even though there appears to be lots of space available?</h2>
|
|
<p>First make sure you've read the sections above about policies, path
|
|
preservation, branch filtering, and the options <strong>minfreespace</strong>,
|
|
<strong>moveonenospc</strong>, <strong>statfs</strong>, and <strong>statfs_ignore</strong>.</p>
|
|
<p>mergerfs is simply presenting a union of the content within multiple
|
|
branches. The reported free space is an aggregate of space available
|
|
within the pool (behavior modified by <strong>statfs</strong> and
|
|
<strong>statfs_ignore</strong>). It does not represent a contiguous space. In the
|
|
same way that read-only filesystems, those with quotas, or reserved
|
|
space report the full theoretical space available.</p>
|
|
<p>Due to path preservation, branch tagging, read-only status, and
|
|
<strong>minfreespace</strong> settings it is perfectly valid that <code>ENOSPC</code> / "out
|
|
of space" / "no space left on device" be returned. It is doing what
|
|
was asked of it: filtering possible branches due to those
|
|
settings. Only one error can be returned and if one of the reasons for
|
|
filtering a branch was <strong>minfreespace</strong> then it will be returned as
|
|
such. <strong>moveonenospc</strong> is only relevant to writing a file which is too
|
|
large for the filesystem it's currently on.</p>
|
|
<p>It is also possible that the filesystem selected has run out of
|
|
inodes. Use <code>df -i</code> to list the total and available inodes per
|
|
filesystem.</p>
|
|
<p>If you don't care about path preservation then simply change the
|
|
<code>create</code> policy to one which isn't. <code>mfs</code> is probably what most are
|
|
looking for. The reason it's not default is because it was originally
|
|
set to <code>epmfs</code> and changing it now would change people's setup. Such a
|
|
setting change will likely occur in mergerfs 3.</p>
|
|
<h2 id="why-does-the-total-available-space-in-mergerfs-not-equal-outside">Why does the total available space in mergerfs not equal outside?</h2>
|
|
<p>Are you using ext2/3/4? With reserve for root? mergerfs uses available
|
|
space for statfs calculations. If you've reserved space for root then
|
|
it won't show up.</p>
|
|
<p>You can remove the reserve by running: <code>tune2fs -m 0 <device></code></p>
|
|
<h2 id="i-notice-massive-slowdowns-of-writes-when-enabling-cachefiles">I notice massive slowdowns of writes when enabling cache.files.</h2>
|
|
<p>When file caching is enabled in any form (<code>cache.files!=off</code>) it will
|
|
issue <code>getxattr</code> requests for <code>security.capability</code> prior to <em>every
|
|
single write</em>. This will usually result in performance degradation,
|
|
especially when using a network filesystem (such as NFS or SMB.)
|
|
Unfortunately at this moment, the kernel is not caching the response.</p>
|
|
<p>To work around this situation mergerfs offers a few solutions.</p>
|
|
<ol>
|
|
<li>Set <code>security_capability=false</code>. It will short circuit any call and
|
|
return <code>ENOATTR</code>. This still means though that mergerfs will
|
|
receive the request before every write but at least it doesn't get
|
|
passed through to the underlying filesystem.</li>
|
|
<li>Set <code>xattr=noattr</code>. Same as above but applies to <em>all</em> calls to
|
|
getxattr. Not just <code>security.capability</code>. This will not be cached
|
|
by the kernel either but mergerfs' runtime config system will still
|
|
function.</li>
|
|
<li>Set <code>xattr=nosys</code>. Results in mergerfs returning <code>ENOSYS</code> which
|
|
<em>will</em> be cached by the kernel. No future xattr calls will be
|
|
forwarded to mergerfs. The downside is that also means the xattr
|
|
based config and query functionality won't work either.</li>
|
|
<li>Disable file caching. If you aren't using applications which use
|
|
<code>mmap</code> it's probably simpler to just disable it altogether. The
|
|
kernel won't send the requests when caching is disabled.</li>
|
|
</ol>
|
|
<h2 id="why-cant-i-see-my-files-directories">Why can't I see my files / directories?</h2>
|
|
<p>It's almost always a permissions issue. Unlike mhddfs and
|
|
unionfs-fuse, which runs as root and attempts to access content as
|
|
such, mergerfs always changes its credentials to that of the
|
|
caller. This means that if the user does not have access to a file or
|
|
directory than neither will mergerfs. However, because mergerfs is
|
|
creating a union of paths it may be able to read some files and
|
|
directories on one filesystem but not another resulting in an
|
|
incomplete set.</p>
|
|
<p>Whenever you run into a split permission issue (seeing some but not
|
|
all files) try using
|
|
<a href="https://github.com/trapexit/mergerfs-tools">mergerfs.fsck</a> tool to
|
|
check for and fix the mismatch. If you aren't seeing anything at all
|
|
be sure that the basic permissions are correct. The user and group
|
|
values are correct and that directories have their executable bit
|
|
set. A common mistake by users new to Linux is to <code>chmod -R 644</code> when
|
|
they should have <code>chmod -R u=rwX,go=rX</code>.</p>
|
|
<p>If using a network filesystem such as NFS or SMB (Samba) be sure to
|
|
pay close attention to anything regarding permissioning and
|
|
users. Root squashing and user translation for instance has bitten a
|
|
few mergerfs users. Some of these also affect the use of mergerfs from
|
|
container platforms such as Docker.</p>
|
|
<h2 id="why-use-fuse-why-not-a-kernel-based-solution">Why use FUSE? Why not a kernel based solution?</h2>
|
|
<p>As with any solution to a problem, there are advantages and
|
|
disadvantages to each one.</p>
|
|
<p>A FUSE based solution has all the downsides of FUSE:</p>
|
|
<ul>
|
|
<li>Higher IO latency due to the trips in and out of kernel space</li>
|
|
<li>Higher general overhead due to trips in and out of kernel space</li>
|
|
<li>Double caching when using page caching</li>
|
|
<li>Misc limitations due to FUSE's design</li>
|
|
</ul>
|
|
<p>But FUSE also has a lot of upsides:</p>
|
|
<ul>
|
|
<li>Easier to offer a cross platform solution</li>
|
|
<li>Easier forward and backward compatibility</li>
|
|
<li>Easier updates for users</li>
|
|
<li>Easier and faster release cadence</li>
|
|
<li>Allows more flexibility in design and features</li>
|
|
<li>Overall easier to write, secure, and maintain</li>
|
|
<li>Much lower barrier to entry (getting code into the kernel takes a
|
|
lot of time and effort initially)</li>
|
|
</ul>
|
|
<h2 id="is-my-oss-libfuse-needed-for-mergerfs-to-work">Is my OS's libfuse needed for mergerfs to work?</h2>
|
|
<p>No. Normally <code>mount.fuse</code> is needed to get mergerfs (or any FUSE
|
|
filesystem to mount using the <code>mount</code> command but in vendoring the
|
|
libfuse library the <code>mount.fuse</code> app has been renamed to
|
|
<code>mount.mergerfs</code> meaning the filesystem type in <code>fstab</code> can simply be
|
|
<code>mergerfs</code>. That said there should be no harm in having it installed
|
|
and continuing to using <code>fuse.mergerfs</code> as the type in <code>/etc/fstab</code>.</p>
|
|
<p>If <code>mergerfs</code> doesn't work as a type it could be due to how the
|
|
<code>mount.mergerfs</code> tool was installed. Must be in <code>/sbin/</code> with proper
|
|
permissions.</p>
|
|
<h2 id="why-was-splice-support-removed">Why was splice support removed?</h2>
|
|
<p>After a lot of testing over the years, splicing always appeared to
|
|
at best, provide equivalent performance, and in some cases, worse
|
|
performance. Splice is not supported on other platforms forcing a
|
|
traditional read/write fallback to be provided. The splice code was
|
|
removed to simplify the codebase.</p>
|
|
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