mergerfs/config/options/index.html


<!doctype html>
<html lang="en" class="no-js">
  <head>
    
      <meta charset="utf-8">
      <meta name="viewport" content="width=device-width,initial-scale=1">
      
        <meta name="description" content="mergerfs - a featureful union filesystem">
      
      
        <link rel="canonical" href="https://trapexit.github.io/mergerfs/config/options/">
      
      
        <link rel="prev" href="../../terminology/">
      
      
        <link rel="next" href="../deprecated_options/">
      
      
      <link rel="icon" href="../../assets/images/favicon.png">
      <meta name="generator" content="mkdocs-1.6.1, mkdocs-material-9.5.50">
    
    
        <title>Options - mergerfs</title>
      
    
      <link rel="stylesheet" href="../../assets/stylesheets/main.a40c8224.min.css">
      
        
        <link rel="stylesheet" href="../../assets/stylesheets/palette.06af60db.min.css">
      
      
        <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
        <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Roboto:300,300i,400,400i,700,700i%7CRoboto+Mono:400,400i,700,700i&display=fallback">
        <style>:root{--md-text-font:"Roboto";--md-code-font:"Roboto Mono"}</style>
      
    
    <script>__md_scope=new URL("../..",location),__md_hash=e=>[...e].reduce(((e,_)=>(e<<5)-e+_.charCodeAt(0)),0),__md_get=(e,_=localStorage,t=__md_scope)=>JSON.parse(_.getItem(t.pathname+"."+e)),__md_set=(e,_,t=localStorage,a=__md_scope)=>{try{t.setItem(a.pathname+"."+e,JSON.stringify(_))}catch(e){}}</script>
    
      
  </head>
  
  
    <body dir="ltr" data-md-color-scheme="default" data-md-color-primary="indigo" data-md-color-accent="indigo">
  
    
    <input class="md-toggle" data-md-toggle="drawer" type="checkbox" id="__drawer" autocomplete="off">
    <input class="md-toggle" data-md-toggle="search" type="checkbox" id="__search" autocomplete="off">
    <label class="md-overlay" for="__drawer"></label>
    <div data-md-component="skip">
      
        
        <a href="#options" class="md-skip">
          Skip to content
        </a>
      
    </div>
    <div data-md-component="announce">
      
    </div>
    
    
<header class="md-header md-header--shadow" data-md-component="header">
  <nav class="md-header__inner md-grid" aria-label="Header">
    <a href="../.." title="mergerfs" class="md-header__button md-logo" aria-label="mergerfs" data-md-component="logo">
      
  <img src="../../logo.jpeg" alt="logo">

    </a>
    <label class="md-header__button md-icon" for="__drawer">
      
      <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M3 6h18v2H3zm0 5h18v2H3zm0 5h18v2H3z"/></svg>
    </label>
    <div class="md-header__title" data-md-component="header-title">
      <div class="md-header__ellipsis">
        <div class="md-header__topic">
          <span class="md-ellipsis">
            mergerfs
          </span>
        </div>
        <div class="md-header__topic" data-md-component="header-topic">
          <span class="md-ellipsis">
            
              Options
            
          </span>
        </div>
      </div>
    </div>
    
      
        <form class="md-header__option" data-md-component="palette">
  
    
    <input class="md-option" data-md-color-media="(prefers-color-scheme)" data-md-color-scheme="default" data-md-color-primary="indigo" data-md-color-accent="indigo"  aria-label="Switch to light mode"  type="radio" name="__palette" id="__palette_0">
    
      <label class="md-header__button md-icon" title="Switch to light mode" for="__palette_1" hidden>
        <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="m14.3 16-.7-2h-3.2l-.7 2H7.8L11 7h2l3.2 9zM20 8.69V4h-4.69L12 .69 8.69 4H4v4.69L.69 12 4 15.31V20h4.69L12 23.31 15.31 20H20v-4.69L23.31 12zm-9.15 3.96h2.3L12 9z"/></svg>
      </label>
    
  
    <input class="md-option" data-md-color-media="(prefers-color-scheme: light)" data-md-color-scheme="default" data-md-color-primary="indigo" data-md-color-accent="indigo"  aria-label="Switch to dark mode"  type="radio" name="__palette" id="__palette_1">
    
      <label class="md-header__button md-icon" title="Switch to dark mode" for="__palette_2" hidden>
        <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M12 8a4 4 0 0 0-4 4 4 4 0 0 0 4 4 4 4 0 0 0 4-4 4 4 0 0 0-4-4m0 10a6 6 0 0 1-6-6 6 6 0 0 1 6-6 6 6 0 0 1 6 6 6 6 0 0 1-6 6m8-9.31V4h-4.69L12 .69 8.69 4H4v4.69L.69 12 4 15.31V20h4.69L12 23.31 15.31 20H20v-4.69L23.31 12z"/></svg>
      </label>
    
  
    <input class="md-option" data-md-color-media="(prefers-color-scheme: dark)" data-md-color-scheme="slate" data-md-color-primary="indigo" data-md-color-accent="indigo"  aria-label="Switch to system preference"  type="radio" name="__palette" id="__palette_2">
    
      <label class="md-header__button md-icon" title="Switch to system preference" for="__palette_0" hidden>
        <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M12 18c-.89 0-1.74-.2-2.5-.55C11.56 16.5 13 14.42 13 12s-1.44-4.5-3.5-5.45C10.26 6.2 11.11 6 12 6a6 6 0 0 1 6 6 6 6 0 0 1-6 6m8-9.31V4h-4.69L12 .69 8.69 4H4v4.69L.69 12 4 15.31V20h4.69L12 23.31 15.31 20H20v-4.69L23.31 12z"/></svg>
      </label>
    
  
</form>
      
    
      <script>var palette=__md_get("__palette");if(palette&&palette.color){if("(prefers-color-scheme)"===palette.color.media){var media=matchMedia("(prefers-color-scheme: light)"),input=document.querySelector(media.matches?"[data-md-color-media='(prefers-color-scheme: light)']":"[data-md-color-media='(prefers-color-scheme: dark)']");palette.color.media=input.getAttribute("data-md-color-media"),palette.color.scheme=input.getAttribute("data-md-color-scheme"),palette.color.primary=input.getAttribute("data-md-color-primary"),palette.color.accent=input.getAttribute("data-md-color-accent")}for(var[key,value]of Object.entries(palette.color))document.body.setAttribute("data-md-color-"+key,value)}</script>
    
    
      <label class="md-header__button md-icon" for="__search">
        
        <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M9.5 3A6.5 6.5 0 0 1 16 9.5c0 1.61-.59 3.09-1.56 4.23l.27.27h.79l5 5-1.5 1.5-5-5v-.79l-.27-.27A6.52 6.52 0 0 1 9.5 16 6.5 6.5 0 0 1 3 9.5 6.5 6.5 0 0 1 9.5 3m0 2C7 5 5 7 5 9.5S7 14 9.5 14 14 12 14 9.5 12 5 9.5 5"/></svg>
      </label>
      <div class="md-search" data-md-component="search" role="dialog">
  <label class="md-search__overlay" for="__search"></label>
  <div class="md-search__inner" role="search">
    <form class="md-search__form" name="search">
      <input type="text" class="md-search__input" name="query" aria-label="Search" placeholder="Search" autocapitalize="off" autocorrect="off" autocomplete="off" spellcheck="false" data-md-component="search-query" required>
      <label class="md-search__icon md-icon" for="__search">
        
        <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M9.5 3A6.5 6.5 0 0 1 16 9.5c0 1.61-.59 3.09-1.56 4.23l.27.27h.79l5 5-1.5 1.5-5-5v-.79l-.27-.27A6.52 6.52 0 0 1 9.5 16 6.5 6.5 0 0 1 3 9.5 6.5 6.5 0 0 1 9.5 3m0 2C7 5 5 7 5 9.5S7 14 9.5 14 14 12 14 9.5 12 5 9.5 5"/></svg>
        
        <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M20 11v2H8l5.5 5.5-1.42 1.42L4.16 12l7.92-7.92L13.5 5.5 8 11z"/></svg>
      </label>
      <nav class="md-search__options" aria-label="Search">
        
          <a href="javascript:void(0)" class="md-search__icon md-icon" title="Share" aria-label="Share" data-clipboard data-clipboard-text="" data-md-component="search-share" tabindex="-1">
            
            <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M18 16.08c-.76 0-1.44.3-1.96.77L8.91 12.7c.05-.23.09-.46.09-.7s-.04-.47-.09-.7l7.05-4.11c.54.5 1.25.81 2.04.81a3 3 0 0 0 3-3 3 3 0 0 0-3-3 3 3 0 0 0-3 3c0 .24.04.47.09.7L8.04 9.81C7.5 9.31 6.79 9 6 9a3 3 0 0 0-3 3 3 3 0 0 0 3 3c.79 0 1.5-.31 2.04-.81l7.12 4.15c-.05.21-.08.43-.08.66 0 1.61 1.31 2.91 2.92 2.91s2.92-1.3 2.92-2.91A2.92 2.92 0 0 0 18 16.08"/></svg>
          </a>
        
        <button type="reset" class="md-search__icon md-icon" title="Clear" aria-label="Clear" tabindex="-1">
          
          <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M19 6.41 17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12z"/></svg>
        </button>
      </nav>
      
    </form>
    <div class="md-search__output">
      <div class="md-search__scrollwrap" tabindex="0" data-md-scrollfix>
        <div class="md-search-result" data-md-component="search-result">
          <div class="md-search-result__meta">
            Initializing search
          </div>
          <ol class="md-search-result__list" role="presentation"></ol>
        </div>
      </div>
    </div>
  </div>
</div>
    
    
      <div class="md-header__source">
        <a href="https://github.com/trapexit/mergerfs" title="Go to repository" class="md-source" data-md-component="source">
  <div class="md-source__icon md-icon">
    
    <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!--! Font Awesome Free 6.7.2 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2024 Fonticons, Inc.--><path d="M439.55 236.05 244 40.45a28.87 28.87 0 0 0-40.81 0l-40.66 40.63 51.52 51.52c27.06-9.14 52.68 16.77 43.39 43.68l49.66 49.66c34.23-11.8 61.18 31 35.47 56.69-26.49 26.49-70.21-2.87-56-37.34L240.22 199v121.85c25.3 12.54 22.26 41.85 9.08 55a34.34 34.34 0 0 1-48.55 0c-17.57-17.6-11.07-46.91 11.25-56v-123c-20.8-8.51-24.6-30.74-18.64-45L142.57 101 8.45 235.14a28.86 28.86 0 0 0 0 40.81l195.61 195.6a28.86 28.86 0 0 0 40.8 0l194.69-194.69a28.86 28.86 0 0 0 0-40.81"/></svg>
  </div>
  <div class="md-source__repository">
    mergerfs
  </div>
</a>
      </div>
    
  </nav>
  
</header>
    
    <div class="md-container" data-md-component="container">
      
      
      <main class="md-main" data-md-component="main">
        <div class="md-main__inner md-grid">
          
            
              <div class="md-sidebar md-sidebar--primary" data-md-component="sidebar" data-md-type="navigation" >
                <div class="md-sidebar__scrollwrap">
                  <div class="md-sidebar__inner">
                    

<nav class="md-nav md-nav--primary" aria-label="Navigation" data-md-level="0">
  <label class="md-nav__title" for="__drawer">
    <a href="../.." title="mergerfs" class="md-nav__button md-logo" aria-label="mergerfs" data-md-component="logo">
      
  <img src="../../logo.jpeg" alt="logo">

    </a>
    mergerfs
  </label>
  
    <div class="md-nav__source">
      <a href="https://github.com/trapexit/mergerfs" title="Go to repository" class="md-source" data-md-component="source">
  <div class="md-source__icon md-icon">
    
    <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!--! Font Awesome Free 6.7.2 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2024 Fonticons, Inc.--><path d="M439.55 236.05 244 40.45a28.87 28.87 0 0 0-40.81 0l-40.66 40.63 51.52 51.52c27.06-9.14 52.68 16.77 43.39 43.68l49.66 49.66c34.23-11.8 61.18 31 35.47 56.69-26.49 26.49-70.21-2.87-56-37.34L240.22 199v121.85c25.3 12.54 22.26 41.85 9.08 55a34.34 34.34 0 0 1-48.55 0c-17.57-17.6-11.07-46.91 11.25-56v-123c-20.8-8.51-24.6-30.74-18.64-45L142.57 101 8.45 235.14a28.86 28.86 0 0 0 0 40.81l195.61 195.6a28.86 28.86 0 0 0 40.8 0l194.69-194.69a28.86 28.86 0 0 0 0-40.81"/></svg>
  </div>
  <div class="md-source__repository">
    mergerfs
  </div>
</a>
    </div>
  
  <ul class="md-nav__list" data-md-scrollfix>
    
      
    <li class="md-nav__item">
      <a href="../.." class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Home
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../../quickstart/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    QuickStart
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item md-nav__item--nested">
      
        
        <input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_3" >
        
          
          <label class="md-nav__link" for="__nav_3" id="__nav_3_label" tabindex="0">
            
  
  <span class="md-ellipsis">
    Installation
  </span>
  

            <span class="md-nav__icon md-icon"></span>
          </label>
        
        <nav class="md-nav" data-md-level="1" aria-labelledby="__nav_3_label" aria-expanded="false">
          <label class="md-nav__title" for="__nav_3">
            <span class="md-nav__icon md-icon"></span>
            Installation
          </label>
          <ul class="md-nav__list" data-md-scrollfix>
            
              
    <li class="md-nav__item">
      <a href="../../setup/installation/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Installation
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../../setup/upgrade/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Upgrade
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../../setup/build/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Build
  </span>
  

      </a>
    </li>
  

          </ul>
        </nav>
      
    </li>
  

    <li class="md-nav__item">
      <a href="../../terminology/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Terminology
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
      
        
        <input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_5" checked>
        
          
          <label class="md-nav__link" for="__nav_5" id="__nav_5_label" tabindex="0">
            
  
  <span class="md-ellipsis">
    Config
  </span>
  

            <span class="md-nav__icon md-icon"></span>
          </label>
        
        <nav class="md-nav" data-md-level="1" aria-labelledby="__nav_5_label" aria-expanded="true">
          <label class="md-nav__title" for="__nav_5">
            <span class="md-nav__icon md-icon"></span>
            Config
          </label>
          <ul class="md-nav__list" data-md-scrollfix>
            
              
    <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">
    Options
  </span>
  

          <span class="md-nav__icon md-icon"></span>
        </label>
      
      <a href="./" class="md-nav__link md-nav__link--active">
        
  
  <span class="md-ellipsis">
    Options
  </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">
  <a href="#types" class="md-nav__link">
    <span class="md-ellipsis">
      types
    </span>
  </a>
  
</li>
      
        <li class="md-nav__item">
  <a href="#mount-options" class="md-nav__link">
    <span class="md-ellipsis">
      mount options
    </span>
  </a>
  
</li>
      
    </ul>
  
</nav>
      
    </li>
  

    <li class="md-nav__item">
      <a href="../deprecated_options/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Deprecated Options
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../branches/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    branches
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../functions_categories_and_policies/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    functions, categories and policies
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../func_readdir/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    func.readdir
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../rename_and_link/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    rename and link
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../cache/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    caching
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../readahead/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    readahead
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../inodecalc/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    inodecalc
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../threads/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    threads
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../pin-threads/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    pin-threads
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../link_cow/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    link_cow
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../fuse_msg_size/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    fuse_msg_size
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../follow-symlinks/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    follow-symlinks
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../link-exdev/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    link-exdev
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../rename-exdev/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    rename-exdev
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../symlinkify/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    symlinkify
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../nullrw/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    nullrw
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../xattr/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    xattr
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../nfsopenhack/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    nfsopenhack
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../statfs/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    statfs / statvfs
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../flush-on-close/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    flush-on-close
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../export-support/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    export-support
  </span>
  

      </a>
    </li>
  

          </ul>
        </nav>
      
    </li>
  

    <li class="md-nav__item">
      <a href="../../error_handling_and_logging/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Error Handling and Logging
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../../runtime_interfaces/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Runtime Interfaces
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../../remote_filesystems/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Remote Filesystems
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../../tips_notes/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Tips and Notes
  </span>
  

      </a>
    </li>
  

    <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>
  

    <li class="md-nav__item">
      <a href="../../project_comparisons/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Project Comparisons
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../../performance/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Tweaking Performance
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../../benchmarking/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Benchmarking
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../../tooling/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Tooling
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../../usage_patterns/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Usage Patterns
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item md-nav__item--nested">
      
        
        <input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_16" >
        
          
          <label class="md-nav__link" for="__nav_16" id="__nav_16_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_16_label" aria-expanded="false">
          <label class="md-nav__title" for="__nav_16">
            <span class="md-nav__icon md-icon"></span>
            FAQ
          </label>
          <ul class="md-nav__list" data-md-scrollfix>
            
              
    <li class="md-nav__item">
      <a href="../../faq/reliability_and_scalability/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Reliability and Scalability
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../../faq/usage_and_functionality/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Usage and Functionality
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../../faq/configuration_and_policies/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Configuration and Policies
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../../faq/compatibility_and_integration/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Compatibility and Integration
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../../faq/recommendations_and_warnings/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Recommendations and Warnings
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../../faq/technical_behavior_and_limitations/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Technical Behavior and Limitations
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../../faq/limit_drive_spinup/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Limiting drive spinup
  </span>
  

      </a>
    </li>
  

          </ul>
        </nav>
      
    </li>
  

    <li class="md-nav__item">
      <a href="../../related_projects/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Related Projects
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../../media_and_publicity/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Media and Publicity
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../../support/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Support
  </span>
  

      </a>
    </li>
  

    <li class="md-nav__item">
      <a href="../../sponsorship_and_donations/" class="md-nav__link">
        
  
  <span class="md-ellipsis">
    Sponsorship and Donations
  </span>
  

      </a>
    </li>
  

  </ul>
</nav>
                  </div>
                </div>
              </div>
            
            
              <div class="md-sidebar md-sidebar--secondary" data-md-component="sidebar" data-md-type="toc" >
                <div class="md-sidebar__scrollwrap">
                  <div class="md-sidebar__inner">
                    

<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">
  <a href="#types" class="md-nav__link">
    <span class="md-ellipsis">
      types
    </span>
  </a>
  
</li>
      
        <li class="md-nav__item">
  <a href="#mount-options" class="md-nav__link">
    <span class="md-ellipsis">
      mount options
    </span>
  </a>
  
</li>
      
    </ul>
  
</nav>
                  </div>
                </div>
              </div>
            
          
            <div class="md-content" data-md-component="content">
              <article class="md-content__inner md-typeset">
                
                  
    <a href="https://github.com/trapexit/mergerfs/edit/master/mkdocs/docs/config/options.md" title="Edit this page" class="md-content__button md-icon">
      
      <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>
    </a>
  
  
    <a href="https://github.com/trapexit/mergerfs/raw/master/mkdocs/docs/config/options.md" title="View source of this page" class="md-content__button md-icon">
      
      <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M17 18c.56 0 1 .44 1 1s-.44 1-1 1-1-.44-1-1 .44-1 1-1m0-3c-2.73 0-5.06 1.66-6 4 .94 2.34 3.27 4 6 4s5.06-1.66 6-4c-.94-2.34-3.27-4-6-4m0 6.5a2.5 2.5 0 0 1-2.5-2.5 2.5 2.5 0 0 1 2.5-2.5 2.5 2.5 0 0 1 2.5 2.5 2.5 2.5 0 0 1-2.5 2.5M9.27 20H6V4h7v5h5v4.07c.7.08 1.36.25 2 .49V8l-6-6H6a2 2 0 0 0-2 2v16a2 2 0 0 0 2 2h4.5a8.2 8.2 0 0 1-1.23-2"/></svg>
    </a>
  

<h1 id="options">Options</h1>
<p>These options are the same regardless of whether you use them with the
<code>mergerfs</code> commandline program, in fstab, or in a config file.</p>
<h3 id="types">types</h3>
<ul>
<li>BOOL = 'true' | 'false'</li>
<li>INT = [MIN_INT,MAX_INT]</li>
<li>UINT = [0,MAX_INT]</li>
<li>SIZE = 'NNM'; NN = INT, M = 'K' | 'M' | 'G' | 'T'</li>
<li>STR = string (may refer to an enumerated value, see details of
  argument)</li>
<li>FUNC = filesystem function</li>
<li>CATEGORY = function category</li>
<li>POLICY = mergerfs function policy</li>
</ul>
<h3 id="mount-options">mount options</h3>
<ul>
<li><strong>config</strong>: Path to a config file. Same arguments as below in
  key=val / ini style format.</li>
<li><strong>branches</strong>: Colon delimited list of branches.</li>
<li><strong>minfreespace=SIZE</strong>: The minimum space value used for creation
  policies. Can be overridden by branch specific option. Understands
  'K', 'M', and 'G' to represent kilobyte, megabyte, and gigabyte
  respectively. (default: 4G)</li>
<li><strong>moveonenospc=BOOL|POLICY</strong>: When enabled if a <strong>write</strong> fails with
  <strong>ENOSPC</strong> (no space left on device) or <strong>EDQUOT</strong> (disk quota
  exceeded) the policy selected will run to find a new location for
  the file. An attempt to move the file to that branch will occur
  (keeping all metadata possible) and if successful the original is
  unlinked and the write retried. (default: false, true = mfs)</li>
<li><strong>inodecalc=passthrough|path-hash|devino-hash|hybrid-hash</strong>: Selects
  the inode calculation algorithm. (default: hybrid-hash)</li>
<li><strong>dropcacheonclose=BOOL</strong>: When a file is requested to be closed
  call <code>posix_fadvise</code> on it first to instruct the kernel that we no
  longer need the data and it can drop its cache. Recommended when
  <strong>cache.files=partial|full|auto-full|per-process</strong> to limit double
  caching. (default: false)</li>
<li><strong>direct-io-allow-mmap=BOOL</strong>: On newer kernels (&gt;= 6.6) it is
  possible to disable file page caching while still allowing for
  shared mmap support. mergerfs will enable this feature if available
  but an option is provided to turn it off for testing and debugging
  purposes. (default: true)</li>
<li><strong>symlinkify=BOOL</strong>: When enabled and a file is not writable and its
  mtime or ctime is older than <strong>symlinkify_timeout</strong> files will be
  reported as symlinks to the original files. Please read more below
  before using. (default: false)</li>
<li><strong>symlinkify_timeout=UINT</strong>: Time to wait, in seconds, to activate
  the <strong>symlinkify</strong> behavior. (default: 3600)</li>
<li><strong>nullrw=BOOL</strong>: Turns reads and writes into no-ops. The request
  will succeed but do nothing. Useful for benchmarking
  mergerfs. (default: false)</li>
<li><strong>lazy-umount-mountpoint=BOOL</strong>: mergerfs will attempt to "lazy
  umount" the mountpoint before mounting itself. Useful when
  performing live upgrades of mergerfs. May not work on
  FreeBSD. (default: false)</li>
<li><strong>ignorepponrename=BOOL</strong>: Ignore path preserving on
  rename. Typically rename and link act differently depending on the
  policy of <code>create</code> (read below). Enabling this will cause rename and
  link to always use the non-path preserving behavior. This means
  files, when renamed or linked, will stay on the same
  filesystem. (default: false)</li>
<li><strong>export-support=BOOL</strong>: Sets a low-level FUSE feature intended to
  indicate the filesystem can support being exported via
  NFS. (default: true)</li>
<li><strong>security_capability=BOOL</strong>: If false return ENOATTR when xattr
  security.capability is queried. (default: true)</li>
<li><strong>xattr=passthrough|noattr|nosys</strong>: Runtime control of
  xattrs. Default is to passthrough xattr requests. 'noattr' will
  short circuit as if nothing exists. 'nosys' will respond with ENOSYS
  as if xattrs are not supported or disabled. (default: passthrough)</li>
<li><strong>link_cow=BOOL</strong>: When enabled if a regular file is opened which
  has a link count &gt; 1 it will copy the file to a temporary file and
  rename over the original. Breaking the link and providing a basic
  copy-on-write function similar to cow-shell. (default: false)</li>
<li><strong>statfs=base|full</strong>: Controls how statfs works. 'base' means it
  will always use all branches in statfs calculations. 'full' is in
  effect path preserving and only includes branches where the path
  exists. (default: base)</li>
<li><strong>statfs_ignore=none|ro|nc</strong>: 'ro' will cause statfs calculations to
  ignore available space for branches mounted or tagged as 'read-only'
  or 'no create'. 'nc' will ignore available space for branches tagged
  as 'no create'. (default: none)</li>
<li><strong>nfsopenhack=off|git|all</strong>: A workaround for exporting mergerfs
  over NFS where there are issues with creating files for write while
  setting the mode to read-only. (default: off)</li>
<li><strong>branches-mount-timeout=UINT</strong>: Number of seconds to wait at
  startup for branches to be a mount other than the mountpoint's
  filesystem. (default: 0)</li>
<li><strong>follow-symlinks=never|directory|regular|all</strong>: Turns symlinks into
  what they point to. (default: never)</li>
<li><strong>link-exdev=passthrough|rel-symlink|abs-base-symlink|abs-pool-symlink</strong>:
  When a link fails with EXDEV optionally create a symlink to the file
  instead.</li>
<li><strong>rename-exdev=passthrough|rel-symlink|abs-symlink</strong>: When a rename
  fails with EXDEV optionally move the file to a special directory and
  symlink to it.</li>
<li><strong>readahead=UINT</strong>: Set readahead (in kilobytes) for mergerfs and
  branches if greater than 0. (default: 0)</li>
<li><strong>posix_acl=BOOL</strong>: Enable POSIX ACL support (if supported by kernel
  and underlying filesystem). (default: false)</li>
<li><strong>async_read=BOOL</strong>: Perform reads asynchronously. If disabled or
  unavailable the kernel will ensure there is at most one pending read
  request per file handle and will attempt to order requests by
  offset. (default: true)</li>
<li><strong>fuse_msg_size=UINT</strong>: Set the max number of pages per FUSE
  message. Only available on Linux &gt;= 4.20 and ignored
  otherwise. (min: 1; max: 256; default: 256)</li>
<li><strong>threads=INT</strong>: Number of threads to use. When used alone
  (<code>process-thread-count=-1</code>) it sets the number of threads reading
  and processing FUSE messages. When used together it sets the number
  of threads reading from FUSE. When set to zero it will attempt to
  discover and use the number of logical cores. If the thread count is
  set negative it will look up the number of cores then divide by the
  absolute value. ie. threads=-2 on an 8 core machine will result in 8
  / 2 = 4 threads. There will always be at least 1 thread. If set to
  -1 in combination with <code>process-thread-count</code> then it will try to
  pick reasonable values based on CPU thread count. NOTE: higher
  number of threads increases parallelism but usually decreases
  throughput. (default: 0)</li>
<li><strong>read-thread-count=INT</strong>: Alias for <code>threads</code>.</li>
<li><strong>process-thread-count=INT</strong>: Enables separate thread pool to
  asynchronously process FUSE requests. In this mode
  <code>read-thread-count</code> refers to the number of threads reading FUSE
  messages which are dispatched to process threads. -1 means disabled
  otherwise acts like <code>read-thread-count</code>. (default: -1)</li>
<li><strong>process-thread-queue-depth=UINT</strong>: Sets the number of requests any
  single process thread can have queued up at one time. Meaning the
  total memory usage of the queues is queue depth multiplied by the
  number of process threads plus read thread count. 0 sets the depth
  to the same as the process thread count. (default: 0)</li>
<li><strong>pin-threads=STR</strong>: Selects a strategy to pin threads to CPUs
  (default: unset)</li>
<li><strong>flush-on-close=never|always|opened-for-write</strong>: Flush data cache
  on file close. Mostly for when writeback is enabled or merging
  network filesystems. (default: opened-for-write)</li>
<li><strong>scheduling-priority=INT</strong>: Set mergerfs' scheduling
  priority. Valid values range from -20 to 19. See <code>setpriority</code> man
  page for more details. (default: -10)</li>
<li><strong>fsname=STR</strong>: Sets the name of the filesystem as seen in
  <strong>mount</strong>, <strong>df</strong>, etc. Defaults to a list of the source paths
  concatenated together with the longest common prefix removed.</li>
<li><strong>func.FUNC=POLICY</strong>: Sets the specific FUSE function's policy. See
  below for the list of value types. Example: <strong>func.getattr=newest</strong></li>
<li><strong>func.readdir=seq|cosr|cor|cosr:INT|cor:INT</strong>: Sets <code>readdir</code>
  policy. INT value sets the number of threads to use for
  concurrency. (default: seq)</li>
<li><strong>category.action=POLICY</strong>: Sets policy of all FUSE functions in the
  action category. (default: epall)</li>
<li><strong>category.create=POLICY</strong>: Sets policy of all FUSE functions in the
  create category. (default: epmfs)</li>
<li><strong>category.search=POLICY</strong>: Sets policy of all FUSE functions in the
  search category. (default: ff)</li>
<li><strong>cache.statfs=UINT</strong>: 'statfs' cache timeout in seconds. (default: 0)</li>
<li><strong>cache.attr=UINT</strong>: File attribute cache timeout in
  seconds. (default: 1)</li>
<li><strong>cache.entry=UINT</strong>: File name lookup cache timeout in
  seconds. (default: 1)</li>
<li><strong>cache.negative_entry=UINT</strong>: Negative file name lookup cache
  timeout in seconds. (default: 0)</li>
<li><strong>cache.files=libfuse|off|partial|full|auto-full|per-process</strong>: File
  page caching mode (default: libfuse)</li>
<li><strong>cache.files.process-names=LIST</strong>: A pipe | delimited list of
  process <a href="https://man7.org/linux/man-pages/man5/proc.5.html">comm</a>
  names to enable page caching for when
  <code>cache.files=per-process</code>. (default: "rtorrent|qbittorrent-nox")</li>
<li><strong>cache.writeback=BOOL</strong>: Enable kernel writeback caching (default:
  false)</li>
<li><strong>cache.symlinks=BOOL</strong>: Cache symlinks (if supported by kernel)
  (default: false)</li>
<li><strong>cache.readdir=BOOL</strong>: Cache readdir (if supported by kernel)
  (default: false)</li>
<li><strong>parallel-direct-writes=BOOL</strong>: Allow the kernel to dispatch
  multiple, parallel (non-extending) write requests for files opened
  with <code>cache.files=per-process</code> (if the process is not in <code>process-names</code>)
  or <code>cache.files=off</code>. (This requires kernel support, and was added in v6.2)</li>
</ul>
<p><strong>NOTE:</strong> Options are evaluated in the order listed so if the options
are <strong>func.rmdir=rand,category.action=ff</strong> the <strong>action</strong> category
setting will override the <strong>rmdir</strong> setting.</p>
<p><strong>NOTE:</strong> Always look at the documentation for the version of mergerfs
you're using. Not all features are available in older releases.</p>


              </article>
            </div>
          
          
<script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script>
        </div>
        
          <button type="button" class="md-top md-icon" data-md-component="top" hidden>
  
  <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg>
  Back to top
</button>
        
      </main>
      
        <footer class="md-footer">
  
    
      <nav class="md-footer__inner md-grid" aria-label="Footer" >
        
          
          <a href="../../terminology/" class="md-footer__link md-footer__link--prev" aria-label="Previous: Terminology">
            <div class="md-footer__button md-icon">
              
              <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M20 11v2H8l5.5 5.5-1.42 1.42L4.16 12l7.92-7.92L13.5 5.5 8 11z"/></svg>
            </div>
            <div class="md-footer__title">
              <span class="md-footer__direction">
                Previous
              </span>
              <div class="md-ellipsis">
                Terminology
              </div>
            </div>
          </a>
        
        
          <a href="../deprecated_options/" class="md-footer__link md-footer__link--next" aria-label="Next: Deprecated Options">
            <div class="md-footer__title">
              <span class="md-footer__direction">
                Next
              </span>
              <div class="md-ellipsis">
                Deprecated Options
              </div>
            </div>
            <div class="md-footer__button md-icon">
              
              <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M4 11v2h12l-5.5 5.5 1.42 1.42L19.84 12l-7.92-7.92L10.5 5.5 16 11z"/></svg>
            </div>
          </a>
        
      </nav>
    
  
  <div class="md-footer-meta md-typeset">
    <div class="md-footer-meta__inner md-grid">
      <div class="md-copyright">
  
  
    Made with
    <a href="https://squidfunk.github.io/mkdocs-material/" target="_blank" rel="noopener">
      Material for MkDocs
    </a>
  
</div>
      
    </div>
  </div>
</footer>
      
    </div>
    <div class="md-dialog" data-md-component="dialog">
      <div class="md-dialog__inner md-typeset"></div>
    </div>
    
    
    <script id="__config" type="application/json">{"base": "../..", "features": ["content.action.edit", "content.action.view", "content.code.copy", "content.code.select", "navigation.footer", "navigation.instant", "navigation.instant.prefetch", "navigation.path", "navigation.top", "navigation.tracking", "optimize", "search.share", "toc.follow"], "search": "../../assets/javascripts/workers/search.f8cc74c7.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
    
    
      <script src="../../assets/javascripts/bundle.60a45f97.min.js"></script>
      
    
  </body>
</html>