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Goofys is a high-performance, POSIX-ish Amazon S3 file system written in Go

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Goofys allows you to mount an S3 bucket as a filey system.

It's a Filey System instead of a File System because goofys strives for performance first and POSIX second. Particularly things that are difficult to support on S3 or would translate into more than one round-trip would either fail (random writes) or faked (no per-file permission). Goofys does not have a on disk data cache (checkout catfs), and consistency model is close-to-open.


$ brew cask install osxfuse
$ brew install goofys
  • Or build from source:
$ export GOPATH=$HOME/work
$ go get github.com/kahing/goofys
$ go install github.com/kahing/goofys


$ cat ~/.aws/credentials
aws_access_key_id = AKID1234567890
aws_secret_access_key = MY-SECRET-KEY
$ $GOPATH/bin/goofys <bucket> <mountpoint>
$ $GOPATH/bin/goofys <bucket:prefix> <mountpoint> # if you only want to mount objects under a prefix

Users can also configure credentials via the AWS CLI or the AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY environment variables.

To mount an S3 bucket on startup, make sure the credential is configured for root, and can add this to /etc/fstab:

goofys#bucket   /mnt/mountpoint        fuse     _netdev,allow_other,--file-mode=0666    0       0

Got more questions? Check out questions other people asked


Using --stat-cache-ttl 1s --type-cache-ttl 1s for goofys -ostat_cache_expire=1 for s3fs to simulate cold runs. Detail for the benchmark can be found in bench.sh. Raw data is available as well. Test was run on an EC2 m4.16xlarge in us-west-2a connecting to a bucket in us-west-2. Units are seconds.

Benchmark result

(†) riofs does not wait for HTTP response before returning from release(), so the create files benchmarks do not measure the right thing for it

Benchmark with caching enabled

Enabling --cache has little impact on write speed (since catfs implements a write-through cache) but read has a large variance. Time to first byte is competitive with s3fs which suggests layering fuse filesystems can be a viable approach.

Cached Benchmark result

To run the benchmark, do:

$ cat > ~/.passwd-riofs
export AWS_ACCESS_KEY_ID=AKID1234567890
$ sudo docker run -e BUCKET=$TESTBUCKET -e CACHE=false --rm --privileged --net=host -v  ~/.passwd-riofs:/root/.passwd-riofs -v /tmp/cache:/tmp/cache kahing/goofys-bench
# result will be written to $TESTBUCKET

if CACHE is set to true, the read benchmarks ('Read 1GB' and 'Time to 1st byte') will be cached read.


Copyright (C) 2015 - 2017 Ka-Hing Cheung

Licensed under the Apache License, Version 2.0

Current Status

goofys has been tested under Linux and OS X.

List of non-POSIX behaviors/limitations:

  • only sequential writes supported
  • does not store file mode/owner/group
    • use --(dir|file)-mode or --(uid|gid) options
  • does not support symlink or hardlink
  • ctime, atime is always the same as mtime
  • cannot rename non-empty directories
  • unlink returns success even if file is not present
  • fsync is ignored, files are only flushed on close

In addition to the items above, the following supportable but not yet implemented:

  • creating files larger than 1TB

Compatibility with non-AWS S3

goofys has been tested with the following non-AWS providers:

  • Amplidata
  • DreamObjects (Ceph)
  • EMC Atmos
  • Google Cloud Storage
  • OpenStack Swift
  • S3Proxy
  • Minio (limited)