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From John Watson <j...@disqus.com>
Subject Re: setcompactionthroughput and setstreamthroughput have no effect
Date Sun, 28 Apr 2013 21:49:58 GMT
The help command says 0 to disable:
  setcompactionthroughput <value_in_mb> - Set the MB/s throughput cap for
compaction in the system, or 0 to disable throttling.
  setstreamthroughput  <value_in_mb> - Set the MB/s throughput cap for
streaming in the system, or 0 to disable throttling.

I also set both to 1000 and it also had no effect (just in case the
documentation was incorrect.)



On Sun, Apr 28, 2013 at 2:43 PM, Edward Capriolo <edlinuxguru@gmail.com>wrote:

> Out of curiosity. Why did you decide to set it to 0 rather then 99999.
> Does any documentation anywhere say that setting to 0 disables the feature?
> I have set streamthroughput higher and seen node join improvements. The
> features do work however they are probably not your limiting factor.
> Remember for stream you are setting Mega Bytes per second but network cards
> are measured in Mega Bits per second.
>
>
> On Sun, Apr 28, 2013 at 5:28 PM, John Watson <john@disqus.com> wrote:
>
>> Running these 2 commands are noop IO wise:
>>   nodetool setcompactionthroughput 0
>>   nodetool setstreamtrhoughput 0
>>
>> If trying to recover or rebuild nodes, it would be super helpful to get
>> more than ~120mbit/s of streaming throughput (per session or ~500mbit
>> total) and ~5% IO utilization in (8) 15k disk RAID10 (per cf).
>>
>> Even enabling multithreaded_compaction gives marginal improvements (1
>> additional thread doesn't help all that much and was only measurable in CPU
>> usage).
>>
>> I understand that these processes should take lower priority to servicing
>> reads and writes. However, in emergencies it would be a nice feature to
>> have a switch to recover a cluster ASAP.
>>
>> Thanks,
>>
>> John
>>
>
>

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