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From Edward Capriolo <edlinuxg...@gmail.com>
Subject Re: setcompactionthroughput and setstreamthroughput have no effect
Date Sun, 28 Apr 2013 21:43:01 GMT
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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