zookeeper-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Camille Fournier <cami...@apache.org>
Subject Re: ZK 3.4.5: Very Strange Write Latency Problem?
Date Fri, 21 Feb 2014 01:55:31 GMT
Have you run it writing to a normal disk, not a ram disk?


On Thu, Feb 20, 2014 at 8:50 PM, jmmec <jmmec2009@gmail.com> wrote:

> I should also mention:
>
> During the 20 minute test run, I confirmed that NOTHING was written to the
> "zookeeper.out" file.  So snapshots weren't written, and nothing else was
> written, nothing at all.  It was a very clean run.
>
> Thanks!
>
>
> On Thu, Feb 20, 2014 at 7:44 PM, jmmec <jmmec2009@gmail.com> wrote:
>
> > Hi everyone,
> >
> > I'm new to the list and especially ZooKeeper.  I'm exploring ZK 3.4.5
> with
> > a dummy application (hacked up & simple) that is using the C API with
> async
> > calls.   It creates 100,000 znodes, slowly, where each znode has 133
> bytes
> > of data.  Simple.  :)
> >
> > Although my tool creates znodes slowly (about 84 per second) and CPU /
> RAM
> > / Network / etc is not at all stressed, I am seeing periodically very
> long
> > "write" latency times (76ms+) reported by ZooKeeper.  My independent
> > analysis confirms what ZooKeeper is reporting.  Wow.
> >
> > The one-page PDF file below explains the problem in more detail and
> > includes a chart that shows the periodic write latency delays:
> >
> >
> >
> https://docs.google.com/file/d/0Bww02z29xbYyUFEtbXQzOG9GVDA/edit?usp=sharing&pli=1
> >
> > I don't know much about JAVA and haven't started poking into ZooKeeper,
> > but since ZooKeeper is reporting the latency, then it seems to be coming
> > from ZooKeeper itself.
> >
> > Any idea what might be causing this, or how better to diagnose what might
> > be happening?
> >
> > Thanks so much!
> >
> >
>

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message