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From Carlos Rolo <r...@pythian.com>
Subject Re: Write timeout under load but Read is fine
Date Fri, 06 Mar 2015 08:35:18 GMT
What is the consistency level you are using?
Are you using Thrift or CQL?
Are you using SSDs?
Check if compactions are running when you get the timeouts.

Regards,

Carlos Juzarte Rolo
Cassandra Consultant

Pythian - Love your data

rolo@pythian | Twitter: cjrolo | Linkedin: *linkedin.com/in/carlosjuzarterolo
<http://linkedin.com/in/carlosjuzarterolo>*
Tel: 1649
www.pythian.com

On Thu, Mar 5, 2015 at 9:51 PM, Jan <cnet62@yahoo.com> wrote:

> Hello Jaydeep;
>
> Run *cassandra-stress* with R/W options enabled  for about the same time
> and check if you have dropped packets.
> It would eliminate the client as the source of the error & also give you a
> replicable tool to base subsequent tests/ findings.
>
> Jan/
>
>
>
>
>   On Thursday, March 5, 2015 12:19 PM, Jaydeep Chovatia <
> chovatia.jaydeep@gmail.com> wrote:
>
>
> I have tried increasing timeout to 10000 but no help. Also verified that
> there is no network lost packets.
>
> Jaydeep
>
> On Wed, Mar 4, 2015 at 12:19 PM, Jan <cnet62@yahoo.com> wrote:
>
> HI Jaydeep;
>
>
>    - look at the i/o  on all three nodes
>    - Increase the write_request_timeout_in_ms: 10000
>    - check the time-outs if any on the client inserting the Writes
>    - check the Network for  dropped/lost packets
>
>
> hope this helps
> Jan/
>
>
>
>   On Wednesday, March 4, 2015 12:26 PM, Jaydeep Chovatia <
> chovatia.jaydeep@gmail.com> wrote:
>
>
> Hi,
>
> In my test program when I increase load then I keep getting few "write
> timeout" from Cassandra say every 10~15 mins. My read:write ratio is
> 50:50. My reads are fine but only writes time out.
>
> Here is my Cassandra details:
> Version: 2.0.11
> Ring of 3 nodes with RF=3
> Node configuration: 24 core + 64GB RAM + 2TB
>
> "write_request_timeout_in_ms: 5000", rest of Cassandra.yaml configuration
> is default
>
> I've also checked IO on Cassandra nodes and looks very low (around 5%).
> I've also checked Cassandra log file and do not see any GC happening. Also
> CPU on Cassandra is low (around 20%). I have 20GB data on each node.
>
> My test program creates connection to all three Cassandra nodes and sends
> read+write request randomly.
>
> Any idea what should I look for?
>
> Jaydeep
>
>
>
>
>
> --
> Jaydeep
>
>
>

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