rclone/docs/content/commands/rclone_nfsmount.md

---
title: "rclone nfsmount"
description: "Mount the remote as file system on a mountpoint."
status: Experimental
versionIntroduced: v1.65
# autogenerated - DO NOT EDIT, instead edit the source code in cmd/nfsmount/ and as part of making a release run "make commanddocs"
---
# rclone nfsmount

Mount the remote as file system on a mountpoint.

## Synopsis

Rclone nfsmount allows Linux, FreeBSD, macOS and Windows to
mount any of Rclone's cloud storage systems as a file system with FUSE.

First set up your remote using `rclone config`.  Check it works with `rclone ls` etc.

On Linux and macOS, you can run mount in either foreground or background (aka
daemon) mode. Mount runs in foreground mode by default. Use the `--daemon` flag
to force background mode. On Windows you can run mount in foreground only,
the flag is ignored.

In background mode rclone acts as a generic Unix mount program: the main
program starts, spawns background rclone process to setup and maintain the
mount, waits until success or timeout and exits with appropriate code
(killing the child process if it fails).

On Linux/macOS/FreeBSD start the mount like this, where `/path/to/local/mount`
is an **empty** **existing** directory:

    rclone nfsmount remote:path/to/files /path/to/local/mount

On Windows you can start a mount in different ways. See [below](#mounting-modes-on-windows)
for details. If foreground mount is used interactively from a console window,
rclone will serve the mount and occupy the console so another window should be
used to work with the mount until rclone is interrupted e.g. by pressing Ctrl-C.

The following examples will mount to an automatically assigned drive,
to specific drive letter `X:`, to path `C:\path\parent\mount`
(where parent directory or drive must exist, and mount must **not** exist,
and is not supported when [mounting as a network drive](#mounting-modes-on-windows)), and
the last example will mount as network share `\\cloud\remote` and map it to an
automatically assigned drive:

    rclone nfsmount remote:path/to/files *
    rclone nfsmount remote:path/to/files X:
    rclone nfsmount remote:path/to/files C:\path\parent\mount
    rclone nfsmount remote:path/to/files \\cloud\remote

When the program ends while in foreground mode, either via Ctrl+C or receiving
a SIGINT or SIGTERM signal, the mount should be automatically stopped.

When running in background mode the user will have to stop the mount manually:

    # Linux
    fusermount -u /path/to/local/mount
    # OS X
    umount /path/to/local/mount

The umount operation can fail, for example when the mountpoint is busy.
When that happens, it is the user's responsibility to stop the mount manually.

The size of the mounted file system will be set according to information retrieved
from the remote, the same as returned by the [rclone about](https://rclone.org/commands/rclone_about/)
command. Remotes with unlimited storage may report the used size only,
then an additional 1 PiB of free space is assumed. If the remote does not
[support](https://rclone.org/overview/#optional-features) the about feature
at all, then 1 PiB is set as both the total and the free size.

## Installing on Windows

To run rclone nfsmount on Windows, you will need to
download and install [WinFsp](http://www.secfs.net/winfsp/).

[WinFsp](https://github.com/winfsp/winfsp) is an open-source
Windows File System Proxy which makes it easy to write user space file
systems for Windows.  It provides a FUSE emulation layer which rclone
uses combination with [cgofuse](https://github.com/winfsp/cgofuse).
Both of these packages are by Bill Zissimopoulos who was very helpful
during the implementation of rclone nfsmount for Windows.

### Mounting modes on windows

Unlike other operating systems, Microsoft Windows provides a different filesystem
type for network and fixed drives. It optimises access on the assumption fixed
disk drives are fast and reliable, while network drives have relatively high latency
and less reliability. Some settings can also be differentiated between the two types,
for example that Windows Explorer should just display icons and not create preview
thumbnails for image and video files on network drives.

In most cases, rclone will mount the remote as a normal, fixed disk drive by default.
However, you can also choose to mount it as a remote network drive, often described
as a network share. If you mount an rclone remote using the default, fixed drive mode
and experience unexpected program errors, freezes or other issues, consider mounting
as a network drive instead.

When mounting as a fixed disk drive you can either mount to an unused drive letter,
or to a path representing a **nonexistent** subdirectory of an **existing** parent
directory or drive. Using the special value `*` will tell rclone to
automatically assign the next available drive letter, starting with Z: and moving backward.
Examples:

    rclone nfsmount remote:path/to/files *
    rclone nfsmount remote:path/to/files X:
    rclone nfsmount remote:path/to/files C:\path\parent\mount
    rclone nfsmount remote:path/to/files X:

Option `--volname` can be used to set a custom volume name for the mounted
file system. The default is to use the remote name and path.

To mount as network drive, you can add option `--network-mode`
to your nfsmount command. Mounting to a directory path is not supported in
this mode, it is a limitation Windows imposes on junctions, so the remote must always
be mounted to a drive letter.

    rclone nfsmount remote:path/to/files X: --network-mode

A volume name specified with `--volname` will be used to create the network share path.
A complete UNC path, such as `\\cloud\remote`, optionally with path
`\\cloud\remote\madeup\path`, will be used as is. Any other
string will be used as the share part, after a default prefix `\\server\`.
If no volume name is specified then `\\server\share` will be used.
You must make sure the volume name is unique when you are mounting more than one drive,
or else the mount command will fail. The share name will treated as the volume label for
the mapped drive, shown in Windows Explorer etc, while the complete
`\\server\share` will be reported as the remote UNC path by
`net use` etc, just like a normal network drive mapping.

If you specify a full network share UNC path with `--volname`, this will implicitly
set the `--network-mode` option, so the following two examples have same result:

    rclone nfsmount remote:path/to/files X: --network-mode
    rclone nfsmount remote:path/to/files X: --volname \\server\share

You may also specify the network share UNC path as the mountpoint itself. Then rclone
will automatically assign a drive letter, same as with `*` and use that as
mountpoint, and instead use the UNC path specified as the volume name, as if it were
specified with the `--volname` option. This will also implicitly set
the `--network-mode` option. This means the following two examples have same result:

    rclone nfsmount remote:path/to/files \\cloud\remote
    rclone nfsmount remote:path/to/files * --volname \\cloud\remote

There is yet another way to enable network mode, and to set the share path,
and that is to pass the "native" libfuse/WinFsp option directly:
`--fuse-flag --VolumePrefix=\server\share`. Note that the path
must be with just a single backslash prefix in this case.


*Note:* In previous versions of rclone this was the only supported method.

[Read more about drive mapping](https://en.wikipedia.org/wiki/Drive_mapping)

See also [Limitations](#limitations) section below.

### Windows filesystem permissions

The FUSE emulation layer on Windows must convert between the POSIX-based
permission model used in FUSE, and the permission model used in Windows,
based on access-control lists (ACL).

The mounted filesystem will normally get three entries in its access-control list (ACL),
representing permissions for the POSIX permission scopes: Owner, group and others.
By default, the owner and group will be taken from the current user, and the built-in
group "Everyone" will be used to represent others. The user/group can be customized
with FUSE options "UserName" and "GroupName",
e.g. `-o UserName=user123 -o GroupName="Authenticated Users"`.
The permissions on each entry will be set according to [options](#options)
`--dir-perms` and `--file-perms`, which takes a value in traditional Unix
[numeric notation](https://en.wikipedia.org/wiki/File-system_permissions#Numeric_notation).

The default permissions corresponds to `--file-perms 0666 --dir-perms 0777`,
i.e. read and write permissions to everyone. This means you will not be able
to start any programs from the mount. To be able to do that you must add
execute permissions, e.g. `--file-perms 0777 --dir-perms 0777` to add it
to everyone. If the program needs to write files, chances are you will
have to enable [VFS File Caching](#vfs-file-caching) as well (see also
[limitations](#limitations)). Note that the default write permission have
some restrictions for accounts other than the owner, specifically it lacks
the "write extended attributes", as explained next.

The mapping of permissions is not always trivial, and the result you see in
Windows Explorer may not be exactly like you expected. For example, when setting
a value that includes write access for the group or others scope, this will be
mapped to individual permissions "write attributes", "write data" and
"append data", but not "write extended attributes". Windows will then show this
as basic permission "Special" instead of "Write", because "Write" also covers
the "write extended attributes" permission. When setting digit 0 for group or
others, to indicate no permissions, they will still get individual permissions
"read attributes", "read extended attributes" and "read permissions". This is
done for compatibility reasons, e.g. to allow users without additional
permissions to be able to read basic metadata about files like in Unix.

WinFsp 2021 (version 1.9) introduced a new FUSE option "FileSecurity",
that allows the complete specification of file security descriptors using
[SDDL](https://docs.microsoft.com/en-us/windows/win32/secauthz/security-descriptor-string-format).
With this you get detailed control of the resulting permissions, compared
to use of the POSIX permissions described above, and no additional permissions
will be added automatically for compatibility with Unix. Some example use
cases will following.

If you set POSIX permissions for only allowing access to the owner,
using `--file-perms 0600 --dir-perms 0700`, the user group and the built-in
"Everyone" group will still be given some special permissions, as described
above. Some programs may then (incorrectly) interpret this as the file being
accessible by everyone, for example an SSH client may warn about "unprotected
private key file". You can work around this by specifying
`-o FileSecurity="D:P(A;;FA;;;OW)"`, which sets file all access (FA) to the
owner (OW), and nothing else.

When setting write permissions then, except for the owner, this does not
include the "write extended attributes" permission, as mentioned above.
This may prevent applications from writing to files, giving permission denied
error instead. To set working write permissions for the built-in "Everyone"
group, similar to what it gets by default but with the addition of the
"write extended attributes", you can specify
`-o FileSecurity="D:P(A;;FRFW;;;WD)"`, which sets file read (FR) and file
write (FW) to everyone (WD). If file execute (FX) is also needed, then change
to `-o FileSecurity="D:P(A;;FRFWFX;;;WD)"`, or set file all access (FA) to
get full access permissions, including delete, with
`-o FileSecurity="D:P(A;;FA;;;WD)"`.

### Windows caveats

Drives created as Administrator are not visible to other accounts,
not even an account that was elevated to Administrator with the
User Account Control (UAC) feature. A result of this is that if you mount
to a drive letter from a Command Prompt run as Administrator, and then try
to access the same drive from Windows Explorer (which does not run as
Administrator), you will not be able to see the mounted drive.

If you don't need to access the drive from applications running with
administrative privileges, the easiest way around this is to always
create the mount from a non-elevated command prompt.

To make mapped drives available to the user account that created them
regardless if elevated or not, there is a special Windows setting called
[linked connections](https://docs.microsoft.com/en-us/troubleshoot/windows-client/networking/mapped-drives-not-available-from-elevated-command#detail-to-configure-the-enablelinkedconnections-registry-entry)
that can be enabled.

It is also possible to make a drive mount available to everyone on the system,
by running the process creating it as the built-in SYSTEM account.
There are several ways to do this: One is to use the command-line
utility [PsExec](https://docs.microsoft.com/en-us/sysinternals/downloads/psexec),
from Microsoft's Sysinternals suite, which has option `-s` to start
processes as the SYSTEM account. Another alternative is to run the mount
command from a Windows Scheduled Task, or a Windows Service, configured
to run as the SYSTEM account. A third alternative is to use the
[WinFsp.Launcher infrastructure](https://github.com/winfsp/winfsp/wiki/WinFsp-Service-Architecture)).
Read more in the [install documentation](https://rclone.org/install/).
Note that when running rclone as another user, it will not use
the configuration file from your profile unless you tell it to
with the [`--config`](https://rclone.org/docs/#config-config-file) option.
Note also that it is now the SYSTEM account that will have the owner
permissions, and other accounts will have permissions according to the
group or others scopes. As mentioned above, these will then not get the
"write extended attributes" permission, and this may prevent writing to
files. You can work around this with the FileSecurity option, see
example above.

Note that mapping to a directory path, instead of a drive letter,
does not suffer from the same limitations.

## Mounting on macOS

Mounting on macOS can be done either via [built-in NFS server](/commands/rclone_serve_nfs/), [macFUSE](https://osxfuse.github.io/) 
(also known as osxfuse) or [FUSE-T](https://www.fuse-t.org/). macFUSE is a traditional
FUSE driver utilizing a macOS kernel extension (kext). FUSE-T is an alternative FUSE system
which "mounts" via an NFSv4 local server.

#### Unicode Normalization

It is highly recommended to keep the default of `--no-unicode-normalization=false`
for all `mount` and `serve` commands on macOS. For details, see [vfs-case-sensitivity](https://rclone.org/commands/rclone_mount/#vfs-case-sensitivity).

### NFS mount

This method spins up an NFS server using [serve nfs](/commands/rclone_serve_nfs/) command and mounts
it to the specified mountpoint. If you run this in background mode using |--daemon|, you will need to
send SIGTERM signal to the rclone process using |kill| command to stop the mount.

Note that `--nfs-cache-handle-limit` controls the maximum number of cached file handles stored by the `nfsmount` caching handler.
This should not be set too low or you may experience errors when trying to access files. The default is 1000000,
but consider lowering this limit if the server's system resource usage causes problems.

### macFUSE Notes

If installing macFUSE using [dmg packages](https://github.com/osxfuse/osxfuse/releases) from
the website, rclone will locate the macFUSE libraries without any further intervention.
If however, macFUSE is installed using the [macports](https://www.macports.org/) package manager,
the following addition steps are required.

    sudo mkdir /usr/local/lib
    cd /usr/local/lib
    sudo ln -s /opt/local/lib/libfuse.2.dylib

### FUSE-T Limitations, Caveats, and Notes

There are some limitations, caveats, and notes about how it works. These are current as 
of FUSE-T version 1.0.14.

#### ModTime update on read

As per the [FUSE-T wiki](https://github.com/macos-fuse-t/fuse-t/wiki#caveats):

> File access and modification times cannot be set separately as it seems to be an 
> issue with the NFS client which always modifies both. Can be reproduced with 
> 'touch -m' and 'touch -a' commands

This means that viewing files with various tools, notably macOS Finder, will cause rlcone
to update the modification time of the file. This may make rclone upload a full new copy
of the file.
    
#### Read Only mounts

When mounting with `--read-only`, attempts to write to files will fail *silently* as
opposed to with a clear warning as in macFUSE.

## Limitations

Without the use of `--vfs-cache-mode` this can only write files
sequentially, it can only seek when reading.  This means that many
applications won't work with their files on an rclone mount without
`--vfs-cache-mode writes` or `--vfs-cache-mode full`.
See the [VFS File Caching](#vfs-file-caching) section for more info.
When using NFS mount on macOS, if you don't specify |--vfs-cache-mode|
the mount point will be read-only.

The bucket-based remotes (e.g. Swift, S3, Google Compute Storage, B2)
do not support the concept of empty directories, so empty
directories will have a tendency to disappear once they fall out of
the directory cache.

When `rclone mount` is invoked on Unix with `--daemon` flag, the main rclone
program will wait for the background mount to become ready or until the timeout
specified by the `--daemon-wait` flag. On Linux it can check mount status using
ProcFS so the flag in fact sets **maximum** time to wait, while the real wait
can be less. On macOS / BSD the time to wait is constant and the check is
performed only at the end. We advise you to set wait time on macOS reasonably.

Only supported on Linux, FreeBSD, OS X and Windows at the moment.

## rclone nfsmount vs rclone sync/copy

File systems expect things to be 100% reliable, whereas cloud storage
systems are a long way from 100% reliable. The rclone sync/copy
commands cope with this with lots of retries.  However rclone nfsmount
can't use retries in the same way without making local copies of the
uploads. Look at the [VFS File Caching](#vfs-file-caching)
for solutions to make nfsmount more reliable.

## Attribute caching

You can use the flag `--attr-timeout` to set the time the kernel caches
the attributes (size, modification time, etc.) for directory entries.

The default is `1s` which caches files just long enough to avoid
too many callbacks to rclone from the kernel.

In theory 0s should be the correct value for filesystems which can
change outside the control of the kernel. However this causes quite a
few problems such as
[rclone using too much memory](https://github.com/rclone/rclone/issues/2157),
[rclone not serving files to samba](https://forum.rclone.org/t/rclone-1-39-vs-1-40-mount-issue/5112)
and [excessive time listing directories](https://github.com/rclone/rclone/issues/2095#issuecomment-371141147).

The kernel can cache the info about a file for the time given by
`--attr-timeout`. You may see corruption if the remote file changes
length during this window.  It will show up as either a truncated file
or a file with garbage on the end.  With `--attr-timeout 1s` this is
very unlikely but not impossible.  The higher you set `--attr-timeout`
the more likely it is.  The default setting of "1s" is the lowest
setting which mitigates the problems above.

If you set it higher (`10s` or `1m` say) then the kernel will call
back to rclone less often making it more efficient, however there is
more chance of the corruption issue above.

If files don't change on the remote outside of the control of rclone
then there is no chance of corruption.

This is the same as setting the attr_timeout option in mount.fuse.

## Filters

Note that all the rclone filters can be used to select a subset of the
files to be visible in the mount.

## systemd

When running rclone nfsmount as a systemd service, it is possible
to use Type=notify. In this case the service will enter the started state
after the mountpoint has been successfully set up.
Units having the rclone nfsmount service specified as a requirement
will see all files and folders immediately in this mode.

Note that systemd runs mount units without any environment variables including
`PATH` or `HOME`. This means that tilde (`~`) expansion will not work
and you should provide `--config` and `--cache-dir` explicitly as absolute
paths via rclone arguments.
Since mounting requires the `fusermount` program, rclone will use the fallback
PATH of `/bin:/usr/bin` in this scenario. Please ensure that `fusermount`
is present on this PATH.

## Rclone as Unix mount helper

The core Unix program `/bin/mount` normally takes the `-t FSTYPE` argument
then runs the `/sbin/mount.FSTYPE` helper program passing it mount options
as `-o key=val,...` or `--opt=...`. Automount (classic or systemd) behaves
in a similar way.

rclone by default expects GNU-style flags `--key val`. To run it as a mount
helper you should symlink rclone binary to `/sbin/mount.rclone` and optionally
`/usr/bin/rclonefs`, e.g. `ln -s /usr/bin/rclone /sbin/mount.rclone`.
rclone will detect it and translate command-line arguments appropriately.

Now you can run classic mounts like this:
```
mount sftp1:subdir /mnt/data -t rclone -o vfs_cache_mode=writes,sftp_key_file=/path/to/pem
```

or create systemd mount units:
```
# /etc/systemd/system/mnt-data.mount
[Unit]
Description=Mount for /mnt/data
[Mount]
Type=rclone
What=sftp1:subdir
Where=/mnt/data
Options=rw,_netdev,allow_other,args2env,vfs-cache-mode=writes,config=/etc/rclone.conf,cache-dir=/var/rclone
```

optionally accompanied by systemd automount unit
```
# /etc/systemd/system/mnt-data.automount
[Unit]
Description=AutoMount for /mnt/data
[Automount]
Where=/mnt/data
TimeoutIdleSec=600
[Install]
WantedBy=multi-user.target
```

or add in `/etc/fstab` a line like
```
sftp1:subdir /mnt/data rclone rw,noauto,nofail,_netdev,x-systemd.automount,args2env,vfs_cache_mode=writes,config=/etc/rclone.conf,cache_dir=/var/cache/rclone 0 0
```

or use classic Automountd.
Remember to provide explicit `config=...,cache-dir=...` as a workaround for
mount units being run without `HOME`.

Rclone in the mount helper mode will split `-o` argument(s) by comma, replace `_`
by `-` and prepend `--` to get the command-line flags. Options containing commas
or spaces can be wrapped in single or double quotes. Any inner quotes inside outer
quotes of the same type should be doubled.

Mount option syntax includes a few extra options treated specially:

- `env.NAME=VALUE` will set an environment variable for the mount process.
  This helps with Automountd and Systemd.mount which don't allow setting
  custom environment for mount helpers.
  Typically you will use `env.HTTPS_PROXY=proxy.host:3128` or `env.HOME=/root`
- `command=cmount` can be used to run `cmount` or any other rclone command
  rather than the default `mount`.
- `args2env` will pass mount options to the mount helper running in background
  via environment variables instead of command line arguments. This allows to
  hide secrets from such commands as `ps` or `pgrep`.
- `vv...` will be transformed into appropriate `--verbose=N`
- standard mount options like `x-systemd.automount`, `_netdev`, `nosuid` and alike
  are intended only for Automountd and ignored by rclone.

## VFS - Virtual File System

This command uses the VFS layer. This adapts the cloud storage objects
that rclone uses into something which looks much more like a disk
filing system.

Cloud storage objects have lots of properties which aren't like disk
files - you can't extend them or write to the middle of them, so the
VFS layer has to deal with that. Because there is no one right way of
doing this there are various options explained below.

The VFS layer also implements a directory cache - this caches info
about files and directories (but not the data) in memory.

## VFS Directory Cache

Using the `--dir-cache-time` flag, you can control how long a
directory should be considered up to date and not refreshed from the
backend. Changes made through the VFS will appear immediately or
invalidate the cache.

    --dir-cache-time duration   Time to cache directory entries for (default 5m0s)
    --poll-interval duration    Time to wait between polling for changes. Must be smaller than dir-cache-time. Only on supported remotes. Set to 0 to disable (default 1m0s)

However, changes made directly on the cloud storage by the web
interface or a different copy of rclone will only be picked up once
the directory cache expires if the backend configured does not support
polling for changes. If the backend supports polling, changes will be
picked up within the polling interval.

You can send a `SIGHUP` signal to rclone for it to flush all
directory caches, regardless of how old they are.  Assuming only one
rclone instance is running, you can reset the cache like this:

    kill -SIGHUP $(pidof rclone)

If you configure rclone with a [remote control](/rc) then you can use
rclone rc to flush the whole directory cache:

    rclone rc vfs/forget

Or individual files or directories:

    rclone rc vfs/forget file=path/to/file dir=path/to/dir

## VFS File Buffering

The `--buffer-size` flag determines the amount of memory,
that will be used to buffer data in advance.

Each open file will try to keep the specified amount of data in memory
at all times. The buffered data is bound to one open file and won't be
shared.

This flag is a upper limit for the used memory per open file.  The
buffer will only use memory for data that is downloaded but not not
yet read. If the buffer is empty, only a small amount of memory will
be used.

The maximum memory used by rclone for buffering can be up to
`--buffer-size * open files`.

## VFS File Caching

These flags control the VFS file caching options. File caching is
necessary to make the VFS layer appear compatible with a normal file
system. It can be disabled at the cost of some compatibility.

For example you'll need to enable VFS caching if you want to read and
write simultaneously to a file.  See below for more details.

Note that the VFS cache is separate from the cache backend and you may
find that you need one or the other or both.

    --cache-dir string                     Directory rclone will use for caching.
    --vfs-cache-mode CacheMode             Cache mode off|minimal|writes|full (default off)
    --vfs-cache-max-age duration           Max time since last access of objects in the cache (default 1h0m0s)
    --vfs-cache-max-size SizeSuffix        Max total size of objects in the cache (default off)
    --vfs-cache-min-free-space SizeSuffix  Target minimum free space on the disk containing the cache (default off)
    --vfs-cache-poll-interval duration     Interval to poll the cache for stale objects (default 1m0s)
    --vfs-write-back duration              Time to writeback files after last use when using cache (default 5s)

If run with `-vv` rclone will print the location of the file cache.  The
files are stored in the user cache file area which is OS dependent but
can be controlled with `--cache-dir` or setting the appropriate
environment variable.

The cache has 4 different modes selected by `--vfs-cache-mode`.
The higher the cache mode the more compatible rclone becomes at the
cost of using disk space.

Note that files are written back to the remote only when they are
closed and if they haven't been accessed for `--vfs-write-back`
seconds. If rclone is quit or dies with files that haven't been
uploaded, these will be uploaded next time rclone is run with the same
flags.

If using `--vfs-cache-max-size` or `--vfs-cache-min-free-size` note
that the cache may exceed these quotas for two reasons. Firstly
because it is only checked every `--vfs-cache-poll-interval`. Secondly
because open files cannot be evicted from the cache. When
`--vfs-cache-max-size` or `--vfs-cache-min-free-size` is exceeded,
rclone will attempt to evict the least accessed files from the cache
first. rclone will start with files that haven't been accessed for the
longest. This cache flushing strategy is efficient and more relevant
files are likely to remain cached.

The `--vfs-cache-max-age` will evict files from the cache
after the set time since last access has passed. The default value of
1 hour will start evicting files from cache that haven't been accessed
for 1 hour. When a cached file is accessed the 1 hour timer is reset to 0
and will wait for 1 more hour before evicting. Specify the time with
standard notation, s, m, h, d, w .

You **should not** run two copies of rclone using the same VFS cache
with the same or overlapping remotes if using `--vfs-cache-mode > off`.
This can potentially cause data corruption if you do. You can work
around this by giving each rclone its own cache hierarchy with
`--cache-dir`. You don't need to worry about this if the remotes in
use don't overlap.

### --vfs-cache-mode off

In this mode (the default) the cache will read directly from the remote and write
directly to the remote without caching anything on disk.

This will mean some operations are not possible

  * Files can't be opened for both read AND write
  * Files opened for write can't be seeked
  * Existing files opened for write must have O_TRUNC set
  * Files open for read with O_TRUNC will be opened write only
  * Files open for write only will behave as if O_TRUNC was supplied
  * Open modes O_APPEND, O_TRUNC are ignored
  * If an upload fails it can't be retried

### --vfs-cache-mode minimal

This is very similar to "off" except that files opened for read AND
write will be buffered to disk.  This means that files opened for
write will be a lot more compatible, but uses the minimal disk space.

These operations are not possible

  * Files opened for write only can't be seeked
  * Existing files opened for write must have O_TRUNC set
  * Files opened for write only will ignore O_APPEND, O_TRUNC
  * If an upload fails it can't be retried

### --vfs-cache-mode writes

In this mode files opened for read only are still read directly from
the remote, write only and read/write files are buffered to disk
first.

This mode should support all normal file system operations.

If an upload fails it will be retried at exponentially increasing
intervals up to 1 minute.

### --vfs-cache-mode full

In this mode all reads and writes are buffered to and from disk. When
data is read from the remote this is buffered to disk as well.

In this mode the files in the cache will be sparse files and rclone
will keep track of which bits of the files it has downloaded.

So if an application only reads the starts of each file, then rclone
will only buffer the start of the file. These files will appear to be
their full size in the cache, but they will be sparse files with only
the data that has been downloaded present in them.

This mode should support all normal file system operations and is
otherwise identical to `--vfs-cache-mode` writes.

When reading a file rclone will read `--buffer-size` plus
`--vfs-read-ahead` bytes ahead.  The `--buffer-size` is buffered in memory
whereas the `--vfs-read-ahead` is buffered on disk.

When using this mode it is recommended that `--buffer-size` is not set
too large and `--vfs-read-ahead` is set large if required.

**IMPORTANT** not all file systems support sparse files. In particular
FAT/exFAT do not. Rclone will perform very badly if the cache
directory is on a filesystem which doesn't support sparse files and it
will log an ERROR message if one is detected.

### Fingerprinting

Various parts of the VFS use fingerprinting to see if a local file
copy has changed relative to a remote file. Fingerprints are made
from:

- size
- modification time
- hash

where available on an object.

On some backends some of these attributes are slow to read (they take
an extra API call per object, or extra work per object).

For example `hash` is slow with the `local` and `sftp` backends as
they have to read the entire file and hash it, and `modtime` is slow
with the `s3`, `swift`, `ftp` and `qinqstor` backends because they
need to do an extra API call to fetch it.

If you use the `--vfs-fast-fingerprint` flag then rclone will not
include the slow operations in the fingerprint. This makes the
fingerprinting less accurate but much faster and will improve the
opening time of cached files.

If you are running a vfs cache over `local`, `s3` or `swift` backends
then using this flag is recommended.

Note that if you change the value of this flag, the fingerprints of
the files in the cache may be invalidated and the files will need to
be downloaded again.

## VFS Chunked Reading

When rclone reads files from a remote it reads them in chunks. This
means that rather than requesting the whole file rclone reads the
chunk specified.  This can reduce the used download quota for some
remotes by requesting only chunks from the remote that are actually
read, at the cost of an increased number of requests.

These flags control the chunking:

    --vfs-read-chunk-size SizeSuffix        Read the source objects in chunks (default 128M)
    --vfs-read-chunk-size-limit SizeSuffix  Max chunk doubling size (default off)
    --vfs-read-chunk-streams int            The number of parallel streams to read at once

The chunking behaves differently depending on the `--vfs-read-chunk-streams` parameter.

### `--vfs-read-chunk-streams` == 0

Rclone will start reading a chunk of size `--vfs-read-chunk-size`,
and then double the size for each read. When `--vfs-read-chunk-size-limit` is
specified, and greater than `--vfs-read-chunk-size`, the chunk size for each
open file will get doubled only until the specified value is reached. If the
value is "off", which is the default, the limit is disabled and the chunk size
will grow indefinitely.

With `--vfs-read-chunk-size 100M` and `--vfs-read-chunk-size-limit 0`
the following parts will be downloaded: 0-100M, 100M-200M, 200M-300M, 300M-400M and so on.
When `--vfs-read-chunk-size-limit 500M` is specified, the result would be
0-100M, 100M-300M, 300M-700M, 700M-1200M, 1200M-1700M and so on.

Setting `--vfs-read-chunk-size` to `0` or "off" disables chunked reading.

The chunks will not be buffered in memory.

### `--vfs-read-chunk-streams` > 0

Rclone reads `--vfs-read-chunk-streams` chunks of size
`--vfs-read-chunk-size` concurrently. The size for each read will stay
constant.

This improves performance performance massively on high latency links
or very high bandwidth links to high performance object stores.

Some experimentation will be needed to find the optimum values of
`--vfs-read-chunk-size` and `--vfs-read-chunk-streams` as these will
depend on the backend in use and the latency to the backend.

For high performance object stores (eg AWS S3) a reasonable place to
start might be `--vfs-read-chunk-streams 16` and
`--vfs-read-chunk-size 4M`. In testing with AWS S3 the performance
scaled roughly as the `--vfs-read-chunk-streams` setting.

Similar settings should work for high latency links, but depending on
the latency they may need more `--vfs-read-chunk-streams` in order to
get the throughput.

## VFS Performance

These flags may be used to enable/disable features of the VFS for
performance or other reasons. See also the [chunked reading](#vfs-chunked-reading)
feature.

In particular S3 and Swift benefit hugely from the `--no-modtime` flag
(or use `--use-server-modtime` for a slightly different effect) as each
read of the modification time takes a transaction.

    --no-checksum     Don't compare checksums on up/download.
    --no-modtime      Don't read/write the modification time (can speed things up).
    --no-seek         Don't allow seeking in files.
    --read-only       Only allow read-only access.

Sometimes rclone is delivered reads or writes out of order. Rather
than seeking rclone will wait a short time for the in sequence read or
write to come in. These flags only come into effect when not using an
on disk cache file.

    --vfs-read-wait duration   Time to wait for in-sequence read before seeking (default 20ms)
    --vfs-write-wait duration  Time to wait for in-sequence write before giving error (default 1s)

When using VFS write caching (`--vfs-cache-mode` with value writes or full),
the global flag `--transfers` can be set to adjust the number of parallel uploads of
modified files from the cache (the related global flag `--checkers` has no effect on the VFS).

    --transfers int  Number of file transfers to run in parallel (default 4)

## VFS Case Sensitivity

Linux file systems are case-sensitive: two files can differ only
by case, and the exact case must be used when opening a file.

File systems in modern Windows are case-insensitive but case-preserving:
although existing files can be opened using any case, the exact case used
to create the file is preserved and available for programs to query.
It is not allowed for two files in the same directory to differ only by case.

Usually file systems on macOS are case-insensitive. It is possible to make macOS
file systems case-sensitive but that is not the default.

The `--vfs-case-insensitive` VFS flag controls how rclone handles these
two cases. If its value is "false", rclone passes file names to the remote
as-is. If the flag is "true" (or appears without a value on the
command line), rclone may perform a "fixup" as explained below.

The user may specify a file name to open/delete/rename/etc with a case
different than what is stored on the remote. If an argument refers
to an existing file with exactly the same name, then the case of the existing
file on the disk will be used. However, if a file name with exactly the same
name is not found but a name differing only by case exists, rclone will
transparently fixup the name. This fixup happens only when an existing file
is requested. Case sensitivity of file names created anew by rclone is
controlled by the underlying remote.

Note that case sensitivity of the operating system running rclone (the target)
may differ from case sensitivity of a file system presented by rclone (the source).
The flag controls whether "fixup" is performed to satisfy the target.

If the flag is not provided on the command line, then its default value depends
on the operating system where rclone runs: "true" on Windows and macOS, "false"
otherwise. If the flag is provided without a value, then it is "true".

The `--no-unicode-normalization` flag controls whether a similar "fixup" is
performed for filenames that differ but are [canonically
equivalent](https://en.wikipedia.org/wiki/Unicode_equivalence) with respect to
unicode. Unicode normalization can be particularly helpful for users of macOS,
which prefers form NFD instead of the NFC used by most other platforms. It is
therefore highly recommended to keep the default of `false` on macOS, to avoid
encoding compatibility issues.

In the (probably unlikely) event that a directory has multiple duplicate
filenames after applying case and unicode normalization, the `--vfs-block-norm-dupes`
flag allows hiding these duplicates. This comes with a performance tradeoff, as
rclone will have to scan the entire directory for duplicates when listing a
directory. For this reason, it is recommended to leave this disabled if not
needed. However, macOS users may wish to consider using it, as otherwise, if a
remote directory contains both NFC and NFD versions of the same filename, an odd
situation will occur: both versions of the file will be visible in the mount,
and both will appear to be editable, however, editing either version will
actually result in only the NFD version getting edited under the hood. `--vfs-block-
norm-dupes` prevents this confusion by detecting this scenario, hiding the
duplicates, and logging an error, similar to how this is handled in `rclone
sync`.

## VFS Disk Options

This flag allows you to manually set the statistics about the filing system.
It can be useful when those statistics cannot be read correctly automatically.

    --vfs-disk-space-total-size    Manually set the total disk space size (example: 256G, default: -1)

## Alternate report of used bytes

Some backends, most notably S3, do not report the amount of bytes used.
If you need this information to be available when running `df` on the
filesystem, then pass the flag `--vfs-used-is-size` to rclone.
With this flag set, instead of relying on the backend to report this
information, rclone will scan the whole remote similar to `rclone size`
and compute the total used space itself.

_WARNING._ Contrary to `rclone size`, this flag ignores filters so that the
result is accurate. However, this is very inefficient and may cost lots of API
calls resulting in extra charges. Use it as a last resort and only with caching.



```
rclone nfsmount remote:path /path/to/mountpoint [flags]
```

## Options

```
      --addr string                            IPaddress:Port or :Port to bind server to
      --allow-non-empty                        Allow mounting over a non-empty directory (not supported on Windows)
      --allow-other                            Allow access to other users (not supported on Windows)
      --allow-root                             Allow access to root user (not supported on Windows)
      --async-read                             Use asynchronous reads (not supported on Windows) (default true)
      --attr-timeout Duration                  Time for which file/directory attributes are cached (default 1s)
      --daemon                                 Run mount in background and exit parent process (as background output is suppressed, use --log-file with --log-format=pid,... to monitor) (not supported on Windows)
      --daemon-timeout Duration                Time limit for rclone to respond to kernel (not supported on Windows) (default 0s)
      --daemon-wait Duration                   Time to wait for ready mount from daemon (maximum time on Linux, constant sleep time on OSX/BSD) (not supported on Windows) (default 1m0s)
      --debug-fuse                             Debug the FUSE internals - needs -v
      --default-permissions                    Makes kernel enforce access control based on the file mode (not supported on Windows)
      --devname string                         Set the device name - default is remote:path
      --dir-cache-time Duration                Time to cache directory entries for (default 5m0s)
      --dir-perms FileMode                     Directory permissions (default 777)
      --direct-io                              Use Direct IO, disables caching of data
      --file-perms FileMode                    File permissions (default 666)
      --fuse-flag stringArray                  Flags or arguments to be passed direct to libfuse/WinFsp (repeat if required)
      --gid uint32                             Override the gid field set by the filesystem (not supported on Windows) (default 1000)
  -h, --help                                   help for nfsmount
      --max-read-ahead SizeSuffix              The number of bytes that can be prefetched for sequential reads (not supported on Windows) (default 128Ki)
      --mount-case-insensitive Tristate        Tell the OS the mount is case insensitive (true) or sensitive (false) regardless of the backend (auto) (default unset)
      --network-mode                           Mount as remote network drive, instead of fixed disk drive (supported on Windows only)
      --nfs-cache-dir string                   The directory the NFS handle cache will use if set
      --nfs-cache-handle-limit int             max file handles cached simultaneously (min 5) (default 1000000)
      --nfs-cache-type memory|disk|symlink     Type of NFS handle cache to use (default memory)
      --no-checksum                            Don't compare checksums on up/download
      --no-modtime                             Don't read/write the modification time (can speed things up)
      --no-seek                                Don't allow seeking in files
      --noappledouble                          Ignore Apple Double (._) and .DS_Store files (supported on OSX only) (default true)
      --noapplexattr                           Ignore all "com.apple.*" extended attributes (supported on OSX only)
  -o, --option stringArray                     Option for libfuse/WinFsp (repeat if required)
      --poll-interval Duration                 Time to wait between polling for changes, must be smaller than dir-cache-time and only on supported remotes (set 0 to disable) (default 1m0s)
      --read-only                              Only allow read-only access
      --sudo                                   Use sudo to run the mount/umount commands as root.
      --uid uint32                             Override the uid field set by the filesystem (not supported on Windows) (default 1000)
      --umask FileMode                         Override the permission bits set by the filesystem (not supported on Windows) (default 002)
      --vfs-block-norm-dupes                   If duplicate filenames exist in the same directory (after normalization), log an error and hide the duplicates (may have a performance cost)
      --vfs-cache-max-age Duration             Max time since last access of objects in the cache (default 1h0m0s)
      --vfs-cache-max-size SizeSuffix          Max total size of objects in the cache (default off)
      --vfs-cache-min-free-space SizeSuffix    Target minimum free space on the disk containing the cache (default off)
      --vfs-cache-mode CacheMode               Cache mode off|minimal|writes|full (default off)
      --vfs-cache-poll-interval Duration       Interval to poll the cache for stale objects (default 1m0s)
      --vfs-case-insensitive                   If a file name not found, find a case insensitive match
      --vfs-disk-space-total-size SizeSuffix   Specify the total space of disk (default off)
      --vfs-fast-fingerprint                   Use fast (less accurate) fingerprints for change detection
      --vfs-read-ahead SizeSuffix              Extra read ahead over --buffer-size when using cache-mode full
      --vfs-read-chunk-size SizeSuffix         Read the source objects in chunks (default 128Mi)
      --vfs-read-chunk-size-limit SizeSuffix   If greater than --vfs-read-chunk-size, double the chunk size after each chunk read, until the limit is reached ('off' is unlimited) (default off)
      --vfs-read-chunk-streams int             The number of parallel streams to read at once
      --vfs-read-wait Duration                 Time to wait for in-sequence read before seeking (default 20ms)
      --vfs-refresh                            Refreshes the directory cache recursively in the background on start
      --vfs-used-is-size rclone size           Use the rclone size algorithm for Used size
      --vfs-write-back Duration                Time to writeback files after last use when using cache (default 5s)
      --vfs-write-wait Duration                Time to wait for in-sequence write before giving error (default 1s)
      --volname string                         Set the volume name (supported on Windows and OSX only)
      --write-back-cache                       Makes kernel buffer writes before sending them to rclone (without this, writethrough caching is used) (not supported on Windows)
```

Options shared with other commands are described next.
See the [global flags page](/flags/) for global options not listed here.

### Filter Options

Flags for filtering directory listings

```
      --delete-excluded                     Delete files on dest excluded from sync
      --exclude stringArray                 Exclude files matching pattern
      --exclude-from stringArray            Read file exclude patterns from file (use - to read from stdin)
      --exclude-if-present stringArray      Exclude directories if filename is present
      --files-from stringArray              Read list of source-file names from file (use - to read from stdin)
      --files-from-raw stringArray          Read list of source-file names from file without any processing of lines (use - to read from stdin)
  -f, --filter stringArray                  Add a file filtering rule
      --filter-from stringArray             Read file filtering patterns from a file (use - to read from stdin)
      --ignore-case                         Ignore case in filters (case insensitive)
      --include stringArray                 Include files matching pattern
      --include-from stringArray            Read file include patterns from file (use - to read from stdin)
      --max-age Duration                    Only transfer files younger than this in s or suffix ms|s|m|h|d|w|M|y (default off)
      --max-depth int                       If set limits the recursion depth to this (default -1)
      --max-size SizeSuffix                 Only transfer files smaller than this in KiB or suffix B|K|M|G|T|P (default off)
      --metadata-exclude stringArray        Exclude metadatas matching pattern
      --metadata-exclude-from stringArray   Read metadata exclude patterns from file (use - to read from stdin)
      --metadata-filter stringArray         Add a metadata filtering rule
      --metadata-filter-from stringArray    Read metadata filtering patterns from a file (use - to read from stdin)
      --metadata-include stringArray        Include metadatas matching pattern
      --metadata-include-from stringArray   Read metadata include patterns from file (use - to read from stdin)
      --min-age Duration                    Only transfer files older than this in s or suffix ms|s|m|h|d|w|M|y (default off)
      --min-size SizeSuffix                 Only transfer files bigger than this in KiB or suffix B|K|M|G|T|P (default off)
```

## See Also

* [rclone](/commands/rclone/)	 - Show help for rclone commands, flags and backends.