zookeeper-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From ibrahim El-sanosi <ibrahimsaba...@gmail.com>
Subject Re: Extremely different readings on different zookeeper deployments
Date Wed, 08 Feb 2017 14:33:31 GMT
This may help as well..
1. The write request  requres consensus (three communcation steps where
read does not).
2. The more write requests the Zab has, the more messages
(Forwards/Proposals/ACKS/Commits messages) will be generated/sent between
Leader/Followers.
3. As (2) occurs, the replics (Leader/Followers) have more messages in
buffer (received queue), so the longer queue, the higer latency.
4. As write increases, the leader (potentially) becomes bottleneck.

N

On Tue, Feb 7, 2017 at 9:01 PM, Michael Han <hanm@cloudera.com> wrote:

> +1 on checking the disk set up first.
>
> Also, it is good to check the server logs on the Windows 7 boxes to see if
> there is anything obviously suspicious. In particular we log warnings if
> flushing the transaction to disk takes longer than a predefined threshold
> (1ms by default). Meanwhile another experiment could isolate the problem is
> to set zookeeper.forceSync
> <https://zookeeper.apache.org/doc/trunk/zookeeperAdmin.html> option to
> false on windows 7 boxes and see if it makes any difference.
>
> On Tue, Feb 7, 2017 at 11:20 AM, Camille Fournier <camille@apache.org>
> wrote:
>
> > Disk writing speed is one of the major factors for zk write performance.
> Is
> > the disk setup the same across both of these machines? My guess is that
> is
> > a big factor.
> >
> > On Tue, Feb 7, 2017 at 2:24 AM, Amar Gajbhiye <Amar.Gajbhiye@1eq.com>
> > wrote:
> >
> > > Hi,
> > > I am working on a distributed system where I want to use consensus
> > > algorithm. I am evaluating ZooKeeper for the same.
> > > I am trying to quantify read and write operations for zookeeper for
> > > version 3.5.2.
> > >
> > > I am running following operations.
> > >
> > >
> > > 1.       Create 50k Znodes with data
> > >
> > > 2.       Read from those 50k znodes
> > >
> > >
> > > I tried this operations when zookeeper server was running on 4
> different
> > > remote servers in standalone mode. My client was always on same
> machine.
> > >
> > >
> > > 1.       Test case 1
> > >
> > > Server configuration : Windows 8 server R2.
> > >
> > > jdk 1.7.0_80
> > >
> > > Avg time required for each write operations : 1.8 ms
> > >
> > > Avg time required for each read operations : 0.9 ms
> > >
> > >
> > >
> > >
> > > 2.       Test case 2
> > >
> > > Server configuration : Windows 8 server R2.
> > >
> > > jdk 1.7.0_21
> > >
> > > Avg time required for each write operation : 1.7 ms
> > >
> > > Avg time required for each read operation : 0.9 ms
> > >
> > >
> > >
> > >
> > >
> > > 3.       Test case 3
> > >
> > > Server configuration : Windows 7
> > >
> > > jdk 1.7.0_25
> > >
> > > Avg time required for each write operation : 35 ms
> > >
> > > Avg time required for each read operation : 0.8 ms
> > >
> > >
> > >
> > >
> > >
> > > 4.       Test case 4
> > >
> > > Server configuration : Windows 7
> > >
> > > jdk1.8.0_101
> > >
> > > Avg time required for each write operation : 40 ms
> > >
> > > Avg time required for each read operation : 0.9 ms
> > >
> > >
> > >
> > >
> > >
> > > 5.       To get network latency out of picture, I kept both client and
> > > server on same machine with following configuration
> > >
> > > Server configuration : Windows 7
> > >
> > > jdk1.8.0_101
> > >
> > > Avg time required for each write operation : 30 ms
> > >
> > > Avg time required for each read operation : 0.4 ms
> > >
> > > Still, I got same readings.
> > >
> > >
> > >
> > > I do not understand, why ZooKeeper gave such a poor write performance
> on
> > > some machines with windows 7. I tried these test cases with different
> jdk
> > > versions. But I am getting same result.
> > >
> > >
> > >
> > > However, Read operation performance was same across all deployments.
> > >
> > >
> > >
> > > Can someone please point out the possible cause for such extreme
> results
> > ?
> > >
> > >
> > >
> > >
> > >
> > > Thanks,
> > >
> > > Amar
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> >
>
>
>
> --
> Cheers
> Michael.
>

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