[Bug 933712] Re: casper configures system to use 50% ram for compressed swap post installation

[Adam Conrad]

To elaborate on Oli's "no known drawbacks" comment, I think it's clear
that some people don't understand how zram works.  While you're telling
it that you can use up to 50% of your RAM for compressed swap, that
doesn't actually kick in until you run out of RAM, precisely the point
where you'd normally be hitting disk for swap instead.

So, if you only ever commit 3.9G on a 4G system, zram does essentially
nothing.  If you overcommit, it'll start swapping from ram to zram and
eating memory, but this all happens so much faster than you can swap to
disk that I have yet to see it be a bad thing (in fact, I've been
arguing for a while that we should just enable zram on all machines,
regardless of configuration).

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https://bugs.launchpad.net/bugs/933712

Title:
  casper configures system to use 50% ram for compressed swap post
  installation

Status in “casper” package in Ubuntu:
  Won't Fix

Bug description:
  When installing from live-cd or if Capser is installed, it leaves
  /usr/share/initramfs-tools/conf.d/comcache with a value
  'COMPCACHE="50%"'. This means that a user will loose half of their RAM
  to a compressed swap device on kernel initramfs generation and reboot.
  . In my opinion this is a _very_ poor user experience.

  A work around is to boot with "nocompcache" as a kernel option.
  However, requiring a user to boot with "nocompcache" is beyond many
  users and will surely frustrate power-users and developers.

  ProblemType: Bug
  DistroRelease: Ubuntu 12.04
  Package: casper (not installed)
  ProcVersionSignature: Ubuntu 3.2.0-15.24-generic 3.2.5
  Uname: Linux 3.2.0-15-generic x86_64
  NonfreeKernelModules: nvidia
  ApportVersion: 1.91-0ubuntu1
  Architecture: amd64
  Date: Thu Feb 16 12:38:37 2012
  EcryptfsInUse: Yes
  SourcePackage: casper
  UpgradeStatus: Upgraded to precise on 2012-01-09 (38 days ago)
  modified.conffile..etc.casper.conf: [deleted]

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