[openstack-dev] [Fuel] Change diagnostic snapshot compression algoritm

Tomasz Napierala tnapierala at mirantis.com
Thu Jan 29 11:30:11 UTC 2015


We have requests for this improvement. It will help with huge environments, we are talking about >5GiB of logs.
Is it on the agenda?


> On 22 Dec 2014, at 07:28, Bartlomiej Piotrowski <bpiotrowski at mirantis.com> wrote:
> FYI, xz with multithreading support (5.2 release) has been marked as stable yesterday.
> Regards,
> Bartłomiej Piotrowski
> On Mon, Nov 24, 2014 at 12:32 PM, Bartłomiej Piotrowski <bpiotrowski at mirantis.com> wrote:
> On 24 Nov 2014, at 12:25, Matthew Mosesohn <mmosesohn at mirantis.com> wrote:
> > I did this exercise over many iterations during Docker container
> > packing and found that as long as the data is under 1gb, it's going to
> > compress really well with xz. Over 1gb and lrzip looks more attractive
> > (but only on high memory systems). In reality, we're looking at log
> > footprints from OpenStack environments on the order of 500mb to 2gb.
> >
> > xz is very slow on single-core systems with 1.5gb of memory, but it's
> > quite a bit faster if you run it on a more powerful system. I've found
> > level 4 compression to be the best compromise that works well enough
> > that it's still far better than gzip. If increasing compression time
> > by 3-5x is too much for you guys, why not just go to bzip? You'll
> > still improve compression but be able to cut back on time.
> >
> > Best Regards,
> > Matthew Mosesohn
> Alpha release of xz supports multithreading via -T (or —threads) parameter.
> We could also use pbzip2 instead of regular bzip to cut some time on multi-core
> systems.
> Regards,
> Bartłomiej Piotrowski
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Tomasz 'Zen' Napierala
Sr. OpenStack Engineer
tnapierala at mirantis.com

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