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Accepted
Janos
Asked: 2018-01-29 06:42:21 +0800 CST

Is libsnappy.so and its variants needed?

  • 772

My Ubuntu 16.04 has libsnappy.so.* files in /usr/lib/i386... folders.

  • Do I need them?

Also, there is a /usr/lib/snapd.glib folder even after I removed snap.

  • Can I just purge all remnants of snap, snapd and snappy related files with brute force?

  • Is there a way to remove them intelligently without leaving residues?

I already did apt autoremove and apt autoclean yet these are still here.

apt ubuntu-core snap

2 Answers

  1. snapd and snappy are two different things.

    snappy is compression used by hadoop

    Wikipedia Snappy compression

    Snappy (previously known as Zippy) is a fast data compression and decompression library written in C++ by Google based on ideas from LZ77 and open-sourced in 2011.2 It does not aim for maximum compression, or compatibility with any other compression library; instead, it aims for very high speeds and reasonable compression. Compression speed is 250 MB/s and decompression speed is 500 MB/s using a single core of a Core i7[which?] processor running in 64-bit mode. The compression ratio is 20–100% lower than gzip.

    snapd - what is snap

    • is a squashFS filesystem containing your app code and a snap.yaml file containing specific metadata. It has a read-only file-system and, once installed, a writable area.

    • is self-contained. It bundles most of the libraries and runtimes it needs and can be updated and reverted without affecting the rest of the system.

    • is confined from the OS and other apps through security mechanisms, but can exchange content and functions with other snaps according to fine-grained policies controlled by the user and the OS defaults.

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  2. Best Answer

    These libraries (libsnappy.so.*) are contained in the following packages:

    $ dpkg -S libsnappy.so
libsnappy1v5:amd64: /usr/lib/x86_64-linux-gnu/libsnappy.so.1.3.0
libsnappy1v5:amd64: /usr/lib/x86_64-linux-gnu/libsnappy.so.1

$ apt-file search libsnappy.so
libsnappy-dev: /usr/lib/x86_64-linux-gnu/libsnappy.so
libsnappy1v5: /usr/lib/x86_64-linux-gnu/libsnappy.so.1
libsnappy1v5: /usr/lib/x86_64-linux-gnu/libsnappy.so.1.3.0

    According to dependencies they are needed on my Ubuntu 16.04 LTS system because of the following reverse dependencies:

    $ apt-cache rdepends libsnappy1v5
libsnappy1v5
Reverse Depends:
  libsnappy-dev
  libavcodec-ffmpeg56
  libavcodec-ffmpeg-extra56
  juju-mongodb3.2
  ceph-test
  ceph
  python3-tables-lib
  python3-tables-dbg
  python-tables-lib
  python-tables-dbg
  python-snappy
  mongodb-server
  mongodb-clients
  libwiredtiger0
  libsnappy-jni
  libshogun16
  librocksdb4.1
  libmtbl0
  libblosc1
  libavcodec-ffmpeg56
  libavcodec-ffmpeg-extra56
  juju-mongodb3.2
  juju-mongodb2.6
  juju-mongodb
  ceph-test
  boomaga
  apitrace-gui
  apitrace
  androguard
  ceph
  libleveldb1v5

    They are used by the following installed packages:

    $ apt-cache rdepends --installed libsnappy1v5 
libsnappy1v5
Reverse Depends:
  libavcodec-ffmpeg-extra56
  python3-tables-lib
  python-tables-lib
  libavcodec-ffmpeg-extra56

    So on my system I can't remove libsnappy1v5 package.

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