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From Alain RODRIGUEZ <arodr...@gmail.com>
Subject Re: High disk read throughput on only one node.
Date Thu, 20 Dec 2012 08:10:26 GMT
"routing more traffic to it?"

So shouldn't I see more "network in" on that node in the AWS console ?

It seems that each node is recieving and sending an equal amount of data.

What value should I use for dynamic-snitch-badness-threshold to give it a
try ?
Le 20 déc. 2012 00:37, "Bryan Talbot" <btalbot@aeriagames.com> a écrit :

> Oh, you're on ec2.  Maybe the dynamic snitch is detecting that one node is
> performing better than the others so is routing more traffic to it?
>
>
> http://www.datastax.com/docs/1.1/configuration/node_configuration#dynamic-snitch-badness-threshold
>
> -Bryan
>
>
>
>
> On Wed, Dec 19, 2012 at 2:30 PM, Alain RODRIGUEZ <arodrime@gmail.com>wrote:
>
>> @Aaron
>> "Is there a sustained difference or did it settle back ? "
>>
>> Sustained, clearly. During the day all nodes read at about 6MB/s while
>> this one reads at 30-40 MB/s. At night while other reads 2MB/s the "broken"
>> nodes reads at 8-10MB/s
>>
>> "Could this have been compaction or repair or upgrade tables working ? "
>>
>> Was my first thought but definitely no. this occurs continuously.
>>
>> "Do the read / write counts available in nodetool cfstats show anything
>> different ? "
>>
>> The cfstats shows different counts (a lot less reads/writes for the "bad"
>> node)  but they didn't join the ring at the same time. I join you the
>> cfstats just in case it could help somehow.
>>
>> Node  38: http://pastebin.com/ViS1MR8d (bad one)
>> Node  32: http://pastebin.com/MrSTHH9F
>> Node 154: http://pastebin.com/7p0Usvwd
>>
>> @Bryan
>>
>>  "clients always connect to that server"
>>
>> I didn't join it in the screenshot from AWS console, but AWS report an
>> (almost) equal network within the nodes (same for output and cpu). The cpu
>> load is a lot higher in the broken node as shown by the OpsCenter, but
>> that's due to the high iowait...)
>>
>
>
>
> --
> Bryan Talbot
> Architect / Platform team lead, Aeria Games and Entertainment
> Silicon Valley | Berlin | Tokyo | Sao Paulo
>
>
>

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