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QFS version 2

QFS version 2.2.6

Release 2.2.6

  • Release 2.2.6 contains go language bindings, bug fixes, and minor improvements. Release notes.

QFS version 2.2.5

Release 2.2.5

  • Release 2.2.5 contains bug fixes and minor improvements. Release notes.

QFS version 2.2.4

Release 2.2.4

Release 2.2.3

  • Support for chunk server's node ID that can be used instead of IP/port for determining if chunk server and QFS client are co-located on the same network node and use chunk server to service client requests.
  • Bug fixes.

Release notes.

QFS version 2.2.2

Release 2.2.2 is a bug fix release. Release notes.

QFS version 2.2.1

Release 2.2.1 is a bug fix release. Release notes.

QFS version 2.2.0

Release 2.2.0 contains symbolic links support, and minor bug fixes.

QFS version 2.1.3

Release 2.1.3 contains DNS resolver's number of open socket accounting bug fix. This bug might manifest itself in at least one non obvious way: chunk server might continuously fail to create or open chunk files if/when the open sockets counter becomes negative.

Release 2.1.2 contains minor bug fixes, meta and chunk servers watchdog.

Release 2.1.1 contains minor bug fixes.

Non blocking DNS resolver is the new feature in release 2.1.0. The new DNS resolver is intended to improve S3 [compatible] object store IO concurrency and reduce latency.

Meta server replication is the major new feature in release 2.0.0. Meta server replication provides automatic meta server fail over. With meta server replication configured QFS does not have single point of failure.

Release notes are available here.

Quantcast File System

Quantcast File System (QFS) is a high-performance, fault-tolerant, distributed file system developed to support MapReduce processing, or other applications reading and writing large files sequentially.

QFS used in Quantcast production cluster.

QFS servers have been tested on 64-bit CentOS 6 extensively and run on Linux variants. The QFS client tools work on OS X and Cygwin as well.

Platform Build Status
Mac OS X Build Status
Ubuntu 14.04 Build Status
Ubuntu 18.04 Build Status
Ubuntu 20.04 Build Status
Ubuntu 22.04 Build Status
CentOS 6 Build Status
CentOS 7 Build Status
CentOS 8 Build Status
Debian 10 Build Status

The implementation details and features of QFS are discussed in detail in the project wiki.

Getting QFS

QFS is available through various channels.

  • BigTop: QFS packages for rpm and debian based systems are available through the BigTop project.
  • Binary Distributions: There are various binary distributions packaged as tarballs available on the Binary Distributions Page.
  • Compile from source: QFS can be compiled on Linux variants, Mac OS X, and Cygwin. See the wiki for more information on how to build QFS yourself.

Trying QFS

Once you have aquired QFS through one of the methods above, you can take QFS for a quick test drive. Setting up a single node configuration to familiarize yourself with QFS is very easy.

  1. Extract the distribution tarball.

    $ tar -xzf qfs.tgz && cd qfs
  2. Set up a single node QFS instance. This will create a workspace in ~/qfsbase, start two chunk servers and one metaserver.

        $ ./examples/sampleservers/ -a install
        Binaries presence checking - OK.
        Setup directories - OK.
        Setup config files - OK.
        Started servers - OK.
  3. Add tools binary path toPATH

    $ PATH=${PWD}/bin/tools:${PATH}
  4. Make a temporary directory on the file system

    $ qfsshell -s localhost -p 20000 -q -- mkdir /qfs/tmp
  5. Create a file containing "Hello World", Reed-Solomon encoded, with replication 1.

        $ echo 'Hello World' | cptoqfs -s localhost -p 20000 -S -k /qfs/tmp/helloworld -d -
  6. Cat the file content.

    $ qfscat -s localhost -p 20000 /qfs/tmp/helloworld
  7. Stat the file to see encoding (RS or not), replication level, and mtime.

    $ qfsshell -s localhost -p 20000 -q -- stat /qfs/tmp/helloworld
  8. Copy the file locally to the current directory.

    $ cpfromqfs -s localhost -p 20000 -k /qfs/tmp/helloworld -d ./helloworld
  9. Remove the file from QFS.

    $ qfsshell -s localhost -p 20000 -q -- rm /qfs/tmp/helloworld
  10. Stop the servers.

    $ ./examples/sampleservers/ -a stop
  11. Uninstall the single node instance.

    $ ./examples/sampleservers/ -a uninstall

Benchmarking QFS

A performance comparison between QFS and HDFS 1.0.2 shows QFS is faster both at reading and writing 20 TB of uncompressed data on our test system, a heterogeneous cluster with 6,500 disk drives. See more information regarding this in our wiki.

Contributing to QFS

We welcome contributions to QFS in the form of enhancement requests, patches, additional tests, bug reports, new ideas, and so on. Please submit issues using our JIRA instance and refer to the QFS code contribution policy when contributing code.

Have Questions?

Join the QFS Developer mailing list or search the archives at the Google Group.

Post comments or questions to


QFS is released under the Apache 2.0 license.