[collectd] dpkg stalling on a loaded collectd aggregator
Shanker Balan
mail at shankerbalan.net
Mon Jul 11 13:07:15 CEST 2011
Hello,
Trent W. Buck wrote,
> > I think I am running into the same problem as described here.
> > http://administratosphere.wordpress.com/2011/05/13/linux-kernel-sync-bug/
>
> I see you already mentioned force-unsafe-io; here's my notes on the
> issue (encountered with a dozen LXC VMs which, sharing a kernel, all
> get synced together).
>
>
> This is because dpkg agressively flushes itself to disk. This is
> especially prevalent in the Ubuntu 10.04 version, which calls sync
> instead of fsync because "fsync is too slow" or some such bullshit.
>
> The problem first arose ca. 1.15.5.6ubuntu2. Current versions have
> --force-unsafe-io to get the old behaviour, which you can put in
> dpkg.cfg (sans leading hyphens); they should also behave substantially
> better even without this.
>
> As force-unsafe-io is absent from 10.04, one must grab eatmydata (from a
> later release) and replace dpkg with a wrapper that uses it:
>
> aptitude install eatmydata -yq
> dpkg-divert --rename /usr/bin/dpkg
> cat >/usr/bin/dpkg <<EOT && chmod +x /usr/bin/dpkg
> #!/bin/sh
> exec eatmydata /usr/bin/dpkg.distrib "\$@"
> EOT
My SA guys decided to move to a newer kernel from
http://www.ubuntuupdates.org/ppa/kernel-ppa?dist=lucid.
They "claim" it fixes it for them. :)
--
http://shankerbalan.net/
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