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From sankalp kohli <kohlisank...@gmail.com>
Subject Re: Streaming performance with 1.2.6
Date Tue, 02 Jul 2013 23:07:12 GMT
I dont know much about streaming in vnodes but you might be hitting this
https://issues.apache.org/jira/browse/CASSANDRA-4650


On Tue, Jul 2, 2013 at 12:43 PM, Mike Heffner <mike@librato.com> wrote:

> 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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