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From Mike Heffner <m...@librato.com>
Subject Re: Streaming performance with 1.2.6
Date Tue, 02 Jul 2013 19:43:10 GMT
As a test, adding a 7th node in the first AZ will stream from both the two
existing nodes in the same AZ.

Aggregate streaming bandwidth at the 7th node is approximately 12 MB/sec
when all limits are set at 800 MB/sec, or about double what I saw streaming
from a single node. This would seem to indicate that the sending node is
limiting our streaming rate.

Mike


On Tue, Jul 2, 2013 at 3:00 PM, Mike Heffner <mike@librato.com> wrote:

> Sankalp,
>
> Parallel sstableloader streaming would definitely be valuable.
>
> However, this ring is currently using vnodes and I was surprised to see
> that a bootstrapping node only streamed from one node in the ring. My
> understanding was that a bootstrapping node would stream from multiple
> nodes in the ring.
>
> We started with a 3 node/3 AZ, RF=3 ring. We then increased that to 6
> nodes, adding one per AZ. The 4th, 5th and 6th nodes only streamed from the
> node in their own AZ/rack which led to the serial sstable streaming. Is
> this the correct behavior for the snitch? Is there an option to stream from
> multiple replicas across the az/rack configuration?
>
> Mike
>
>
> On Tue, Jul 2, 2013 at 1:53 PM, sankalp kohli <kohlisankalp@gmail.com>wrote:
>
>> This was a problem pre vnodes. I had several JIRA for that but some of
>> them were voted down saying the performance will improve with vnodes.
>> The main problem is that it streams one sstable at a time and not in
>> parallel.
>>
>> Jira 4784 can speed up the bootstrap performance. You can also do a zero
>> copy and not touch the caches of the nodes which are contributing in the
>> build.
>>
>>
>> https://issues.apache.org/jira/browse/CASSANDRA-4663
>> https://issues.apache.org/jira/browse/CASSANDRA-4784
>>
>>
>> On Tue, Jul 2, 2013 at 7:35 AM, Mike Heffner <mike@librato.com> wrote:
>>
>>>
>>> On Mon, Jul 1, 2013 at 10:06 PM, Mike Heffner <mike@librato.com> wrote:
>>>
>>>>
>>>> The only changes we've made to the config (aside from dirs/hosts) are:
>>>>
>>>
>>> Forgot to include we've changed this as well:
>>>
>>> -partitioner: org.apache.cassandra.dht.Murmur3Partitioner
>>> +partitioner: org.apache.cassandra.dht.RandomPartitioner
>>>
>>>
>>> Cheers,
>>>
>>> Mike
>>> --
>>>
>>>   Mike Heffner <mike@librato.com>
>>>   Librato, Inc.
>>>
>>>
>>
>
>
> --
>
>   Mike Heffner <mike@librato.com>
>   Librato, Inc.
>
>


-- 

  Mike Heffner <mike@librato.com>
  Librato, Inc.

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