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From Paulo Motta <pauloricard...@gmail.com>
Subject Re: StreamCoordinator.ConnectionsPerHost set to 1
Date Thu, 16 Jun 2016 22:05:36 GMT
Increasing the number of threads alone won't help, because you need to add
connectionsPerHost-awareness to StreamPlan.requestRanges (otherwise only a
single connection per host is created) similar to what was done to
StreamPlan.transferFiles by CASSANDRA-3668, but maybe bit trickier. There's
an open ticket to support that on CASSANDRA-4663

There's also another discussion on improving rebuild parallelism on
CASSANDRA-12015.

2016-06-16 14:43 GMT-03:00 Anubhav Kale <Anubhav.Kale@microsoft.com>:

> Hello,
>
>
>
> I noticed that StreamCoordinator.ConnectionsPerHost is always set to 1
> (Cassandra 2.1.13). If I am reading the code correctly, this means there
> will always be just one socket (well, 2 technically for each direction)
> between nodes when rebuilding thus the data will always be serialized.
>
>
>
> Have folks experimented with increasing this ? It appears that some
> parallelism here might help rebuilds in a significant way assuming we
> aren’t hitting bandwidth caps (it’s a pain for us at the moment to rebuild
> nodes holding 500GB).
>
>
>
> I’m going to try to patch our cluster with a change to test this out, but
> wanted to hear from experts as well.
>
>
>
> Thanks !
>

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