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[Victor Zverovich <1008400@xxxxxxxxxxxxxxxxxx>]

I observe substantial lag under heavy I/O (in my case I was unzipping a
multigigabyte archive) with the deadline scheduler. Manually switching
to the cfq scheduler improved responsiveness and eliminated the lag.
Perhaps cfq is a better choice for the desktop version?

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https://bugs.launchpad.net/bugs/1008400

Title:
  Ubuntu server uses CFQ scheduler instead of deadline

Status in linux package in Ubuntu:
  In Progress

Bug description:
  Ubuntu server now uses the '-generic' kernel, as the '-server' kernel
  doesn't exist anymore. With this change the default server disk
  scheduler changed from deadline to CFQ. This is very bad for servers,
  deadline should absolutely be the default for servers.

  For example we moved some KVM images to an Ubuntu 12.04 server, but we
  had to revert as we got lots of disk errors and eventually frozen
  disks on these KVM's due to write timeouts. It took us a while before
  we found out that this 12.04 server used CFQ, which surprised us a
  lot.

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