[Bug 1095154] Re: initramfs-tools: ZRAM is not used in Live CD's if the machine has more than 512 MB RAM

[Mélodie]

Hi Steve,

In my experience a limit at 512 MB is too low anyhow.

If a limit needs to be fixed it should be at least 10024 MB and not less. About pre allocation : instead of giving the zram devices 50% of the total amount RAM provided by the hardware, 25% would be a good number, which is what the developer of the compcache project advised.
Here is the wiki,
http://code.google.com/p/compcache/w/list

here are benchmarks,
http://code.google.com/p/compcache/w/list?can=2&q=25%25

here on eeepc with Ubuntu, back in 2011:
http://code.google.com/p/compcache/wiki/Eeepc701

(Ubuntu was using 25% of the available ram for the zram module).

I have put test versions of Ubuntu Precise remixes with compache enabled
and not limited in them. I have installed the bigger (a version setup
fully up to date, with Openbox and a panel of applications) to a T30 IBM
Thinkpad having 512 MB RAM. The only annoyance I met with have been the
kernel swapping while less than half of the physical memory was yet
used, which I fixed by configuring swappiness in the sysctl.conf file
(for this annoyance I don't know what should be done : seek for bug
reports at kernel.org maybe ?)

Could this bug report be reopened, and a request to raise the limit RAM
considered ?

Thanks,
Mélodie

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https://bugs.launchpad.net/bugs/1095154

Title:
  initramfs-tools:  ZRAM is not used in Live CD's if the machine has
  more than 512 MB RAM

Status in “initramfs-tools” package in Ubuntu:
  Won't Fix

Bug description:
  The Ubuntu version used in Precise Pangolin;
  The initramfs-tools version used is  0.99ubuntu13:

  I am trying to make a customized Live CD with the ZRAM kernel module
  enabled in the Live. I found the files dedicated to configure it for
  the Live CD, but when I tried the resulting ISO in Virtualbox ZRAM was
  not activated. Then I discovered the file "$WORKDIR/initrd/scripts
  /init-top/compcache", and I found this section in the script:

  ******************************

  # Do not use compcache on the liveCD if we have more than 512M
  if [ "${BOOT}" = "casper" ]; then
      if [ "${TOTAL_RAM}" -gt 524288 ]; then
          exit 0
      fi
  fi

  ******************************

  therefore I restarted Virtualbox with an amount of RAM less than 512M
  to see if this time ZRAM would be enabled and YES it was!

  I think it is a pity to limit the amount of available RAM for a given
  machine where the Live will be used, because it can always be useful,
  and also because the ZRAM swap device will be used only if needed.

  I would like this limitation to be removed.

  The present bug report could be tagged "wish-list" or "low".

  Thanks for considering this request.

  Regards,
  Mélodie

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