Different disk writes per node

[Eric Liou <er...@gmail.com>]

[image: image.png]

I'm seeing different write patterns through out the nodes of my ensemble.
There's one node that's writing around 100MB/min but others doing 6x higher
writes.

The ensemble seems healthy, all nodes serving (not Observer). The instance
is running only Zookeeper with Exhibitor. iotop confirms that the writes
are from the Zookeeper process.
I was expecting that all of them to write roughly the same quantity because
of how broadcast works.

What's actually happening? Should I be worried about this?
Thanks.

Re: Different disk writes per node

[Patrick Hunt <ph...@apache.org>]

Hi Eric. I saw your original post but didn't have anything of value to add.
I've never seen this myself. That said "never seen" not in the sense that
it's impossible, just in the sense that I've never looked for such an issue
and have never noticed such a thing. It does seem unusual however.

Unfortunately you didn't provide detail for speculating further. I'm not
very familiar with Exhibitor (know of it - +cc Jordan in case he has
insights) and without more details such as the version of ZK and in
particular the configs of the 5 servers it's hard to come up with much.
Also, are you able to correlate the outlier to a particular ZK role -
perhaps that's the leader? (although I'm not sure why that would matter...)

Patrick

On Wed, Jan 24, 2018 at 10:28 AM, ercliou <er...@gmail.com> wrote:

> Any pointers that could lead to explanation of this behavior?
> Thanks.
>
>
>
> --
> Sent from: http://zookeeper-user.578899.n2.nabble.com/
>

Re: Different disk writes per node

[ercliou <er...@gmail.com>]

Any pointers that could lead to explanation of this behavior?
Thanks.



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Re: Different disk writes per node

[ercliou <er...@gmail.com>]

<http://zookeeper-user.578899.n2.nabble.com/file/t396470/Screen_Shot_2018-01-08_at_1.png> 

Attaching image, write of ensemble of 5 nodes



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