Re: How many vnodes should I use for each node in my cluster?

[Li, Guangxing]

Thanks for the input. I just kicked off another repair for one keyspace.
Per the log, there are 1536 ranges to repair through. This makes sense:
there are 6 nodes in the cluster, each having 256 token ranges, so 6*256 =
1536. So far, it is averaging 1 range per minute. So repair the keyspace
will take more than a day on this rate. I guess the only thing I can do is
to upgrade to 2.1 and start using incremental repair?

Thanks.

George.

On Fri, Sep 16, 2016 at 3:03 PM, Dor Laor  wrote:

> On Fri, Sep 16, 2016 at 11:29 AM, Li, Guangxing 
> wrote:
>
>> Hi,
>>
>> I have a 3 nodes cluster, each with less than 200 GB data. Currently all
>> nodes have the default 256 value for num_tokens. My colleague told me that
>> with the data size I have (less than 200 GB on each node), I should change
>> num_tokens to something like 32 to get better performance, especially speed
>> up the repair time. Do any of you guys have experience on
>>
>
> It's not enough to know the volume size, it's important to know the amount
> of keys which effect the merkle tree. I wouldn't change it, I doubt you'll
> see a significant difference in repair speed and if you'll grow the cluster
> you would want to have enough vnodes.
>
>
>> this? I am running Cassandra Community version 2.0.9. The cluster resides
>> in AWS. All keyspaces have RC 3.
>>
>> Thanks.
>>
>> George.
>>
>
>

Re: How many vnodes should I use for each node in my cluster?

[Dor Laor]

On Fri, Sep 16, 2016 at 11:29 AM, Li, Guangxing 
wrote:

> Hi,
>
> I have a 3 nodes cluster, each with less than 200 GB data. Currently all
> nodes have the default 256 value for num_tokens. My colleague told me that
> with the data size I have (less than 200 GB on each node), I should change
> num_tokens to something like 32 to get better performance, especially speed
> up the repair time. Do any of you guys have experience on
>

It's not enough to know the volume size, it's important to know the amount
of keys which effect the merkle tree. I wouldn't change it, I doubt you'll
see a significant difference in repair speed and if you'll grow the cluster
you would want to have enough vnodes.


> this? I am running Cassandra Community version 2.0.9. The cluster resides
> in AWS. All keyspaces have RC 3.
>
> Thanks.
>
> George.
>