Hi,

I put together a blog explaining possible reasons for an unbalanced
Cassandra nodes.

http://abiasforaction.net/unbalanced-cassandra-cluster/

Let me know if you have any questions.

Cheers,
Akhil


On Thu, Jun 15, 2017 at 5:54 PM, Affan Syed <as...@an10.io> wrote:

> John,
>
> I am a co-worker with Junaid -- he is out sick, so just wanted to confirm
> that one of your shots in the dark is correct. This is a RF of 1x
>
> "CREATE KEYSPACE orion WITH replication = {'class': 'SimpleStrategy',
> 'replication_factor': '1'}  AND durable_writes = true;"
>
> However, how does the RF affect the redistribution of key/data?
>
> Affan
>
> - Affan
>
> On Wed, Jun 14, 2017 at 1:16 AM, John Hughes <johnthug...@gmail.com>
> wrote:
>
>> OP, I was just looking at your original numbers and I have some questions:
>>
>> 270GB on one node and 414KB on the other, but something close to 50/50 on
>> "Owns(effective)".
>> What replication factor are your keyspaces set up with? 1x or 2x or ??
>>
>> I would say you are seeing 50/50 because the tokens are allocated
>> 50/50(others on the list please correct what are for me really just
>> assumptions!!!!), but I would hazard a guess that your replication factor
>> is still 1x, so it isn't moving anything around. Or your keyspace
>> rplication is incorrect and isn't being distributed(I have had issues with
>> the AWSMultiRegionSnitch and not getting the region correct[us-east vs
>> us-east-1). It doesn't throw an error, but it doesn't work very well either
>> =)
>>
>> Can you do a 'describe keyspace XXX' and show the first line(the CREATE
>> KEYSPACE line).
>>
>> Mind you, these are all just shots in the dark from here.
>>
>> Cheers,
>>
>>
>> On Tue, Jun 13, 2017 at 3:13 AM Junaid Nasir <jna...@an10.io> wrote:
>>
>>> Is the OP expecting a perfect 50%/50% split?
>>>
>>>
>>> best result I got was 240gb/30gb split, which I think is not properly
>>> balanced.
>>>
>>>
>>>> Also, what are your outputs when you call out specific keyspaces? Do
>>>> the numbers get more even?
>>>
>>>
>>> i don't know what you mean by *call out specific key spaces?* can you
>>> please explain that a bit.
>>>
>>>
>>> If your schema is not modelled correctly you can easily end up unevenly
>>>> distributed data.
>>>
>>>
>>> I think that is the problem. initial 270gb data might not by modeled
>>> correctly. I have run a lot of tests on 270gb data including downsizing it
>>> to 5gb, they all resulted in same uneven distribution. I also tested a
>>> dummy dataset of 2gb which was balanced evenly. coming from rdb, I didn't
>>> give much thought to data modeling. can anyone please point me to some
>>> resources regarding this problem.
>>>
>>> On Tue, Jun 13, 2017 at 3:24 AM, Akhil Mehra <akhilme...@gmail.com>
>>> wrote:
>>>
>>>> Great point John.
>>>>
>>>> The OP should also note that data distribution also depends on your
>>>> schema and incoming data profile.
>>>>
>>>> If your schema is not modelled correctly you can easily end up unevenly
>>>> distributed data.
>>>>
>>>> Cheers,
>>>> Akhil
>>>>
>>>> On Tue, Jun 13, 2017 at 3:36 AM, John Hughes <johnthug...@gmail.com>
>>>> wrote:
>>>>
>>>>> Is the OP expecting a perfect 50%/50% split? That, to my experience,
>>>>> is not going to happen, it is almost always shifted from a fraction of a
>>>>> percent to a couple percent.
>>>>>
>>>>> Datacenter: eu-west
>>>>> ===================
>>>>> Status=Up/Down
>>>>> |/ State=Normal/Leaving/Joining/Moving
>>>>> --  Address        Load       Tokens       Owns (effective)  Host ID
>>>>>                             Rack
>>>>> UN  XX.XX.XX.XX    22.71 GiB  256          47.6%
>>>>> 57dafdde-2f62-467c-a8ff-c91e712f89c9  1c
>>>>> UN  XX.XX.XX.XX  17.17 GiB  256          51.3%
>>>>> d2a65c51-087d-48de-ae1f-a41142eb148d  1b
>>>>> UN  XX.XX.XX.XX  26.15 GiB  256          52.4%
>>>>> acf5dd34-5b81-4e5b-b7be-85a7fccd8e1c  1c
>>>>> UN  XX.XX.XX.XX   16.64 GiB  256          50.2%
>>>>> 6c8842dd-a966-467c-a7bc-bd6269ce3e7e  1a
>>>>> UN  XX.XX.XX.XX  24.39 GiB  256          49.8%
>>>>> fd92525d-edf2-4974-8bc5-a350a8831dfa  1a
>>>>> UN  XX.XX.XX.XX   23.8 GiB   256          48.7%
>>>>> bdc597c0-718c-4ef6-b3ef-7785110a9923  1b
>>>>>
>>>>> Though maybe part of what you are experiencing can be cleared up by
>>>>> repair/compaction/cleanup. Also, what are your outputs when you call out
>>>>> specific keyspaces? Do the numbers get more even?
>>>>>
>>>>> Cheers,
>>>>>
>>>>> On Mon, Jun 12, 2017 at 5:22 AM Akhil Mehra <akhilme...@gmail.com>
>>>>> wrote:
>>>>>
>>>>>> auto_bootstrap is true by default. Ensure its set to true. On startup
>>>>>> look at your logs for your auto_bootstrap value.  Look at the node
>>>>>> configuration line in your log file.
>>>>>>
>>>>>> Akhil
>>>>>>
>>>>>> On Mon, Jun 12, 2017 at 6:18 PM, Junaid Nasir <jna...@an10.io> wrote:
>>>>>>
>>>>>>> No, I didn't set it (left it at default value)
>>>>>>>
>>>>>>> On Fri, Jun 9, 2017 at 3:18 AM, ZAIDI, ASAD A <az1...@att.com>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> Did you make sure auto_bootstrap property is indeed set to [true]
>>>>>>>> when you added the node?
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> *From:* Junaid Nasir [mailto:jna...@an10.io]
>>>>>>>> *Sent:* Monday, June 05, 2017 6:29 AM
>>>>>>>> *To:* Akhil Mehra <akhilme...@gmail.com>
>>>>>>>> *Cc:* Vladimir Yudovin <vla...@winguzone.com>;
>>>>>>>> user@cassandra.apache.org
>>>>>>>> *Subject:* Re: Convert single node C* to cluster (rebalancing
>>>>>>>> problem)
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> not evenly, i have setup a new cluster with subset of data (around
>>>>>>>> 5gb). using the configuration above I am getting these results
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Datacenter: datacenter1
>>>>>>>>
>>>>>>>> =======================
>>>>>>>>
>>>>>>>> Status=Up/Down
>>>>>>>>
>>>>>>>> |/ State=Normal/Leaving/Joining/Moving
>>>>>>>>
>>>>>>>> --  Address      Load       Tokens       Owns (effective)  Host ID     
>>>>>>>> Rack
>>>>>>>>
>>>>>>>> UN  10.128.2.1   4.86 GiB   256          44.9%             
>>>>>>>> e4427611-c247-42ee-9404-371e177f5f17  rack1
>>>>>>>>
>>>>>>>> UN  10.128.2.10  725.03 MiB  256         55.1%             
>>>>>>>> 690d5620-99d3-4ae3-aebe-8f33af54a08b  rack1
>>>>>>>>
>>>>>>>> is there anything else I can tweak/check to make the distribution
>>>>>>>> even?
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On Sat, Jun 3, 2017 at 3:30 AM, Akhil Mehra <akhilme...@gmail.com>
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>> So now the data is evenly balanced in both nodes?
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Refer to the following documentation to get a better understanding
>>>>>>>> of the roc_address and the broadcast_rpc_address https://
>>>>>>>> www.instaclustr.com/demystifying-cassandras-broadcast_address/
>>>>>>>> <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.instaclustr.com_demystifying-2Dcassandras-2Dbroadcast-5Faddress_&d=DwMFaQ&c=LFYZ-o9_HUMeMTSQicvjIg&r=FsmDztdsVuIKml8IDhdHdg&m=57WqcUduTb1GA2Ij5E1fXgw3Cf21HYBK_4l2HVryPrk&s=MaTA43pugg78xQNfaOQElhyvd8k7CjVqZPr3IWALdWI&e=>.
>>>>>>>> I am surprised that your node started up with rpc_broadcast_address
>>>>>>>> set as this is an unsupported property. I am assuming you are
>>>>>>>> using Cassandra version 3.10.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Regards,
>>>>>>>>
>>>>>>>> Akhil
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On 2/06/2017, at 11:06 PM, Junaid Nasir <jna...@an10.io> wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> I am able to get it working. I added a new node with following
>>>>>>>> changes
>>>>>>>>
>>>>>>>> #rpc_address:0.0.0.0
>>>>>>>>
>>>>>>>> rpc_address: 10.128.1.11
>>>>>>>>
>>>>>>>> #rpc_broadcast_address:10.128.1.11
>>>>>>>>
>>>>>>>> rpc_address was set to 0.0.0.0, (I ran into a problem previously
>>>>>>>> regarding remote connection and made these changes
>>>>>>>> https://stackoverflow.com/questions/12236898/apache-cassandr
>>>>>>>> a-remote-access
>>>>>>>> <https://urldefense.proofpoint.com/v2/url?u=https-3A__stackoverflow.com_questions_12236898_apache-2Dcassandra-2Dremote-2Daccess&d=DwMFaQ&c=LFYZ-o9_HUMeMTSQicvjIg&r=FsmDztdsVuIKml8IDhdHdg&m=57WqcUduTb1GA2Ij5E1fXgw3Cf21HYBK_4l2HVryPrk&s=oj8BCLiyBDqqVQNqfGohFeujtqlzAkd-uwS878d4mg4&e=>
>>>>>>>> )
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> should it be happening?
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On Thu, Jun 1, 2017 at 6:31 PM, Vladimir Yudovin <
>>>>>>>> vla...@winguzone.com> wrote:
>>>>>>>>
>>>>>>>> Did you run "nodetool cleanup" on first node after second was
>>>>>>>> bootstrapped? It should clean rows not belonging to node after tokens
>>>>>>>> changed.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Best regards, Vladimir Yudovin,
>>>>>>>>
>>>>>>>> *Winguzone
>>>>>>>> <https://urldefense.proofpoint.com/v2/url?u=https-3A__winguzone.com_-3Ffrom-3Dlist&d=DwMFaQ&c=LFYZ-o9_HUMeMTSQicvjIg&r=FsmDztdsVuIKml8IDhdHdg&m=57WqcUduTb1GA2Ij5E1fXgw3Cf21HYBK_4l2HVryPrk&s=Q1M5YRAsw0iUQKOIulEmO72RhdENQCRhpqZSjgxxHos&e=>
>>>>>>>> - Cloud Cassandra Hosting*
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> ---- On Wed, 31 May 2017 03:55:54 -0400 *Junaid Nasir
>>>>>>>> <jna...@an10.io <jna...@an10.io>>* wrote ----
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Cassandra ensure that adding or removing nodes are very easy and
>>>>>>>> that load is balanced between nodes when a change is made. but it's not
>>>>>>>> working in my case.
>>>>>>>>
>>>>>>>> I have a single node C* deployment (with 270 GB of data) and want
>>>>>>>> to load balance the data on multiple nodes, I followed this guide
>>>>>>>> <https://urldefense.proofpoint.com/v2/url?u=https-3A__docs.datastax.com_en_cassandra_2.1_cassandra_operations_ops-5Fadd-5Fnode-5Fto-5Fcluster-5Ft.html&d=DwMFaQ&c=LFYZ-o9_HUMeMTSQicvjIg&r=FsmDztdsVuIKml8IDhdHdg&m=57WqcUduTb1GA2Ij5E1fXgw3Cf21HYBK_4l2HVryPrk&s=xnLuX4qqSZxVuY6Gz2NXRdc6TG8J7at9kDhkhBnWpnM&e=>
>>>>>>>>
>>>>>>>>
>>>>>>>> `nodetool status` shows 2 nodes but load is not balanced between
>>>>>>>> them
>>>>>>>>
>>>>>>>> Datacenter: dc1
>>>>>>>>
>>>>>>>> ===============
>>>>>>>>
>>>>>>>> Status=Up/Down
>>>>>>>>
>>>>>>>> |/ State=Normal/Leaving/Joining/Moving
>>>>>>>>
>>>>>>>> --  Address      Load       Tokens       Owns (effective)  Host ID    
>>>>>>>> Rack
>>>>>>>>
>>>>>>>> UN  10.128.0.7   270.75 GiB  256          48.6%        
>>>>>>>> 1a3f6faa-4376-45a8-9c20-11480ae5664c  rack1
>>>>>>>>
>>>>>>>> UN  10.128.0.14  414.36 KiB  256          51.4%        
>>>>>>>> 66a89fbf-08ba-4b5d-9f10-55d52a199b41  rack1
>>>>>>>>
>>>>>>>> I also ran 'nodetool repair' on new node but result is same. any
>>>>>>>> pointers would be appreciated :)
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> conf file of new node
>>>>>>>>
>>>>>>>> cluster_name: 'cluster1'
>>>>>>>>
>>>>>>>>  - seeds: "10.128.0.7"
>>>>>>>> num_tokens: 256
>>>>>>>>
>>>>>>>> endpoint_snitch: GossipingPropertyFileSnitch
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>>
>>>>>>>> Junaid
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>
>>>
>

Reply via email to