stuck with num_tokens 256

[onmstester onmstester <on...@zoho.com>]

I noticed that currently there is a discussion in ML with subject: changing default token behavior for 4.0. Any recommendation to guys like me who already have multiple clusters ( > 30 nodes in each cluster) with random partitioner and num_tokens = 256? I should also add some nodes to existing clusters, is it possible with num_tokens = 256? How could we fix this bug (reduce num_tokens in existent clusters)? Cassandra version: 3.11.2 Sent using Zoho Mail

Re: stuck with num_tokens 256

[kurt greaves <ku...@instaclustr.com>]

>
> But one more question, should i use num_tokens : 8 (i would follow
> datastax recommendation) and allocate_tokens_for_local_replication_factor=3
> (which is max RF among my keyspaces) for new clusters which i'm going to
> setup?

16 is probably where it's at. Test beforehand though.

> Is the Allocation algorithm, now recommended algorithm and mature enough
> to replace the Random algorithm? if its so, it should be the default one at
> 4.0?

Let's leave that discussion to the other thread on the dev list.

On Sat, 22 Sep 2018 at 20:35, onmstester onmstester <on...@zoho.com>
wrote:

> Thanks,
> Because all my clusters are already balanced, i won't change their config
> But one more question, should i use num_tokens : 8 (i would follow
> datastax recommendation) and allocate_tokens_for_local_replication_factor=3
> (which is max RF among my keyspaces) for new clusters which i'm going to
> setup?
> Is the Allocation algorithm, now recommended algorithm and mature enough
> to replace the Random algorithm? if its so, it should be the default one at
> 4.0?
>
>
> ---- On Sat, 22 Sep 2018 13:41:47 +0330 *kurt greaves
> <kurt@instaclustr.com <ku...@instaclustr.com>>* wrote ----
>
> If you have problems with balance you can add new nodes using the
> algorithm and it'll balance out the cluster. You probably want to stick to
> 256 tokens though.
> To reduce your # tokens you'll have to do a DC migration (best way). Spin
> up a new DC using the algorithm on the nodes and set a lower number of
> tokens. You'll want to test first but if you create a new keyspace for the
> new DC prior to creation of the new nodes with the desired RF (ie. a
> keyspace just in the "new" DC with your RF) then add your nodes using that
> keyspace for allocation tokens *should* be distributed evenly amongst
> that DC, and when migrate you can decommission the old DC and hopefully end
> up with a balanced cluster.
> Definitely test beforehand though because that was just me theorising...
>
> I'll note though that if your existing clusters don't have any major
> issues it's probably not worth the migration at this point.
>
> On Sat, 22 Sep 2018 at 17:40, onmstester onmstester <on...@zoho.com>
> wrote:
>
>
> I noticed that currently there is a discussion in ML with
> subject: changing default token behavior for 4.0.
> Any recommendation to guys like me who already have multiple clusters ( >
> 30 nodes in each cluster) with random partitioner and num_tokens = 256?
> I should also add some nodes to existing clusters, is it possible
> with num_tokens = 256?
> How could we fix this bug (reduce num_tokens in existent clusters)?
> Cassandra version: 3.11.2
>
> Sent using Zoho Mail <https://www.zoho.com/mail/>
>
>
>
>

Re: stuck with num_tokens 256

[onmstester onmstester <on...@zoho.com>]

Thanks, Because all my clusters are already balanced, i won't change their config But one more question, should i use num_tokens : 8 (i would follow datastax recommendation) and allocate_tokens_for_local_replication_factor=3 (which is max RF among my keyspaces) for new clusters which i'm going to setup? Is the Allocation algorithm, now recommended algorithm and mature enough to replace the Random algorithm? if its so, it should be the default one at 4.0? ---- On Sat, 22 Sep 2018 13:41:47 +0330 kurt greaves <ku...@instaclustr.com> wrote ---- If you have problems with balance you can add new nodes using the algorithm and it'll balance out the cluster. You probably want to stick to 256 tokens though. To reduce your # tokens you'll have to do a DC migration (best way). Spin up a new DC using the algorithm on the nodes and set a lower number of tokens. You'll want to test first but if you create a new keyspace for the new DC prior to creation of the new nodes with the desired RF (ie. a keyspace just in the "new" DC with your RF) then add your nodes using that keyspace for allocation tokens should be distributed evenly amongst that DC, and when migrate you can decommission the old DC and hopefully end up with a balanced cluster. Definitely test beforehand though because that was just me theorising... I'll note though that if your existing clusters don't have any major issues it's probably not worth the migration at this point. On Sat, 22 Sep 2018 at 17:40, onmstester onmstester <on...@zoho.com> wrote: I noticed that currently there is a discussion in ML with subject: changing default token behavior for 4.0. Any recommendation to guys like me who already have multiple clusters ( > 30 nodes in each cluster) with random partitioner and num_tokens = 256? I should also add some nodes to existing clusters, is it possible with num_tokens = 256? How could we fix this bug (reduce num_tokens in existent clusters)? Cassandra version: 3.11.2 Sent using Zoho Mail

Re: stuck with num_tokens 256

[kurt greaves <ku...@instaclustr.com>]

No, that's not true.

On Sat., 22 Sep. 2018, 21:58 onmstester onmstester, <on...@zoho.com>
wrote:

>
> If you have problems with balance you can add new nodes using the
> algorithm and it'll balance out the cluster. You probably want to stick to
> 256 tokens though.
>
>
> I read somewhere (don't remember the ref) that all nodes of the cluster
> should use the same algorithm, so if my cluster suffer from imbalanced
> nodes using random algorithm i can not add new nodes that are using
> Allocation algorithm. isn't that correct?
>
>
>

Re: stuck with num_tokens 256

[onmstester onmstester <on...@zoho.com>]

If you have problems with balance you can add new nodes using the algorithm and it'll balance out the cluster. You probably want to stick to 256 tokens though. I read somewhere (don't remember the ref) that all nodes of the cluster should use the same algorithm, so if my cluster suffer from imbalanced nodes using random algorithm i can not add new nodes that are using Allocation algorithm. isn't that correct?

Re: stuck with num_tokens 256

[kurt greaves <ku...@instaclustr.com>]

If you have problems with balance you can add new nodes using the algorithm
and it'll balance out the cluster. You probably want to stick to 256 tokens
though.
To reduce your # tokens you'll have to do a DC migration (best way). Spin
up a new DC using the algorithm on the nodes and set a lower number of
tokens. You'll want to test first but if you create a new keyspace for the
new DC prior to creation of the new nodes with the desired RF (ie. a
keyspace just in the "new" DC with your RF) then add your nodes using that
keyspace for allocation tokens *should* be distributed evenly amongst that
DC, and when migrate you can decommission the old DC and hopefully end up
with a balanced cluster.
Definitely test beforehand though because that was just me theorising...

I'll note though that if your existing clusters don't have any major issues
it's probably not worth the migration at this point.

On Sat, 22 Sep 2018 at 17:40, onmstester onmstester <on...@zoho.com>
wrote:

> I noticed that currently there is a discussion in ML with
> subject: changing default token behavior for 4.0.
> Any recommendation to guys like me who already have multiple clusters ( >
> 30 nodes in each cluster) with random partitioner and num_tokens = 256?
> I should also add some nodes to existing clusters, is it possible
> with num_tokens = 256?
> How could we fix this bug (reduce num_tokens in existent clusters)?
> Cassandra version: 3.11.2
>
> Sent using Zoho Mail <https://www.zoho.com/mail/>
>
>
>