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Posted to user@cassandra.apache.org by DE VITO Dominique <do...@thalesgroup.com> on 2014/08/05 17:19:35 UTC
vnode and NetworkTopologyStrategy: not playing well together ?
Hi,
My understanding is that NetworkTopologyStrategy does NOT play well with vnodes, due to:
* Vnode => tokens are (usually) randomly generated (AFAIK)
* NetworkTopologyStrategy => required carefully choosen tokens for all nodes in order to not to get a VERY unbalanced ring like in https://issues.apache.org/jira/browse/CASSANDRA-3810
When playing with vnodes, is the recommendation to define one rack for the entire cluster ?
Thanks.
Regards,
Dominique
Re: vnode and NetworkTopologyStrategy: not playing well together ?
Posted by Jeremy Jongsma <je...@barchart.com>.
If your nodes are not actually evenly distributed across physical racks for
redundancy, don't use multiple racks.
On Tue, Aug 5, 2014 at 10:57 AM, DE VITO Dominique <
dominique.devito@thalesgroup.com> wrote:
> First, thanks for your answer.
>
> > This is incorrect. Network Topology w/ Vnodes will be fine, assuming
> you've got RF= # of racks.
>
> IMHO, it's not a good enough condition.
> Let's use an example with RF=2
>
> N1/rack_1 N2/rack_1 N3/rack_1 N4/rack_2
>
> Here, you have RF= # of racks
> And due to NetworkTopologyStrategy, N4 will store *all* the cluster data,
> leading to a completely imbalanced cluster.
>
> IMHO, it happens when using nodes *or* vnodes.
>
> As well-balanced clusters with NetworkTopologyStrategy rely on carefully
> chosen token distribution/path along the ring *and* as tokens are
> randomly-generated with vnodes, my guess is that with vnodes and
> NetworkTopologyStrategy, it's better to define a single (logical) rack //
> due to "carefully chosen tokens" vs "randomly-generated token" clash.
>
> I don't see other options left.
> Do you see other ones ?
>
> Regards,
> Dominique
>
>
>
>
> -----Message d'origine-----
> De : jonathan.haddad@gmail.com [mailto:jonathan.haddad@gmail.com] De la
> part de Jonathan Haddad
> Envoyé : mardi 5 août 2014 17:43
> À : user@cassandra.apache.org
> Objet : Re: vnode and NetworkTopologyStrategy: not playing well together ?
>
> This is incorrect. Network Topology w/ Vnodes will be fine, assuming
> you've got RF= # of racks. For each token, replicas are chosen based on
> the strategy. Essentially, you could have a wild imbalance in token
> ownership, but it wouldn't matter because the replicas would be distributed
> across the rest of the machines.
>
>
> http://www.datastax.com/documentation/cassandra/2.0/cassandra/architecture/architectureDataDistributeReplication_c.html
>
> On Tue, Aug 5, 2014 at 8:19 AM, DE VITO Dominique <
> dominique.devito@thalesgroup.com> wrote:
> > Hi,
> >
> >
> >
> > My understanding is that NetworkTopologyStrategy does NOT play well
> > with vnodes, due to:
> >
> > · Vnode => tokens are (usually) randomly generated (AFAIK)
> >
> > · NetworkTopologyStrategy => required carefully choosen tokens
> for
> > all nodes in order to not to get a VERY unbalanced ring like in
> > https://issues.apache.org/jira/browse/CASSANDRA-3810
> >
> >
> >
> > When playing with vnodes, is the recommendation to define one rack for
> > the entire cluster ?
> >
> >
> >
> > Thanks.
> >
> >
> >
> > Regards,
> >
> > Dominique
> >
> >
> >
> >
>
>
>
> --
> Jon Haddad
> http://www.rustyrazorblade.com
> skype: rustyrazorblade
>
RE: vnode and NetworkTopologyStrategy: not playing well together ?
Posted by DE VITO Dominique <do...@thalesgroup.com>.
> The discussion about racks & NTS is also mentioned in this recent article : planetcassandra.org/multi-data-center-replication-in-nosql-databases/
>
> The last section may be of interest for you
Thanks DuyHai.
Note that this section is also part of C* anti-patterns http://www.datastax.com/documentation/cassandra/2.0/cassandra/architecture/architecturePlanningAntiPatterns_c.html
But I think it's missing some advice for vnodes (something like "due to randomly-generated tokens, define one single rack when using vnodes" ??).
D.
[@@ THALES GROUP INTERNAL @@]
De : DuyHai Doan [mailto:doanduyhai@gmail.com]
Envoyé : mardi 5 août 2014 20:07
À : user@cassandra.apache.org
Objet : RE: vnode and NetworkTopologyStrategy: not playing well together ?
The discussion about racks & NTS is also mentioned in this recent article : planetcassandra.org/multi-data-center-replication-in-nosql-databases/<http://planetcassandra.org/multi-data-center-replication-in-nosql-databases/>
The last section may be of interest for you
Le 5 août 2014 18:14, "DE VITO Dominique" <do...@thalesgroup.com>> a écrit :
> Jonathan wrote:
>
> Yes, if you have only 1 machine in a rack then your cluster will be imbalanced. You're going to be able to dream up all sorts of weird failure cases when you choose a scenario like RF=2 & totally imbalanced network arch.
>
> Vnodes attempt to solve the problem of imbalanced rings by choosing so many tokens that it's improbable that the ring will be imbalanced.
Storage/load distro = function(1st replica placement, other replica placement)
vnode solves the balancing pb for 1st replica placement // so, yes, I agree with you, but for 1st replica placement only
But NetworkTopologyStrategy (NTS) influences other (2+) replica placement => as NTS best behavior relies on token distro, and you have no control on tokens with vnodes, the best option I see with **vnode** is to use only one rack with NTS.
Dominique
-----Message d'origine-----
De : jonathan.haddad@gmail.com<ma...@gmail.com> [mailto:jonathan.haddad@gmail.com<ma...@gmail.com>] De la part de Jonathan Haddad
Envoyé : mardi 5 août 2014 18:04
À : user@cassandra.apache.org<ma...@cassandra.apache.org>
Objet : Re: vnode and NetworkTopologyStrategy: not playing well together ?
Yes, if you have only 1 machine in a rack then your cluster will be imbalanced. You're going to be able to dream up all sorts of weird failure cases when you choose a scenario like RF=2 & totally imbalanced network arch.
Vnodes attempt to solve the problem of imbalanced rings by choosing so many tokens that it's improbable that the ring will be imbalanced.
On Tue, Aug 5, 2014 at 8:57 AM, DE VITO Dominique <do...@thalesgroup.com>> wrote:
> First, thanks for your answer.
>
>> This is incorrect. Network Topology w/ Vnodes will be fine, assuming you've got RF= # of racks.
>
> IMHO, it's not a good enough condition.
> Let's use an example with RF=2
>
> N1/rack_1 N2/rack_1 N3/rack_1 N4/rack_2
>
> Here, you have RF= # of racks
> And due to NetworkTopologyStrategy, N4 will store *all* the cluster data, leading to a completely imbalanced cluster.
>
> IMHO, it happens when using nodes *or* vnodes.
>
> As well-balanced clusters with NetworkTopologyStrategy rely on carefully chosen token distribution/path along the ring *and* as tokens are randomly-generated with vnodes, my guess is that with vnodes and NetworkTopologyStrategy, it's better to define a single (logical) rack // due to "carefully chosen tokens" vs "randomly-generated token" clash.
>
> I don't see other options left.
> Do you see other ones ?
>
> Regards,
> Dominique
>
>
>
>
> -----Message d'origine-----
> De : jonathan.haddad@gmail.com<ma...@gmail.com> [mailto:jonathan.haddad@gmail.com<ma...@gmail.com>] De
> la part de Jonathan Haddad Envoyé : mardi 5 août 2014 17:43 À :
> user@cassandra.apache.org<ma...@cassandra.apache.org> Objet : Re: vnode and
> NetworkTopologyStrategy: not playing well together ?
>
> This is incorrect. Network Topology w/ Vnodes will be fine, assuming you've got RF= # of racks. For each token, replicas are chosen based on the strategy. Essentially, you could have a wild imbalance in token ownership, but it wouldn't matter because the replicas would be distributed across the rest of the machines.
>
> http://www.datastax.com/documentation/cassandra/2.0/cassandra/architec
> ture/architectureDataDistributeReplication_c.html
>
> On Tue, Aug 5, 2014 at 8:19 AM, DE VITO Dominique <do...@thalesgroup.com>> wrote:
>> Hi,
>>
>>
>>
>> My understanding is that NetworkTopologyStrategy does NOT play well
>> with vnodes, due to:
>>
>> · Vnode => tokens are (usually) randomly generated (AFAIK)
>>
>> · NetworkTopologyStrategy => required carefully choosen tokens for
>> all nodes in order to not to get a VERY unbalanced ring like in
>> https://issues.apache.org/jira/browse/CASSANDRA-3810
>>
>>
>>
>> When playing with vnodes, is the recommendation to define one rack
>> for the entire cluster ?
>>
>>
>>
>> Thanks.
>>
>>
>>
>> Regards,
>>
>> Dominique
>>
>>
>>
>>
>
>
>
> --
> Jon Haddad
> http://www.rustyrazorblade.com
> skype: rustyrazorblade
--
Jon Haddad
http://www.rustyrazorblade.com
skype: rustyrazorblade
RE: vnode and NetworkTopologyStrategy: not playing well together ?
Posted by DuyHai Doan <do...@gmail.com>.
The discussion about racks & NTS is also mentioned in this recent article :
planetcassandra.org/multi-data-center-replication-in-nosql-databases/
The last section may be of interest for you
Le 5 août 2014 18:14, "DE VITO Dominique" <do...@thalesgroup.com>
a écrit :
> > Jonathan wrote:
> >
> > Yes, if you have only 1 machine in a rack then your cluster will be
> imbalanced. You're going to be able to dream up all sorts of weird failure
> cases when you choose a scenario like RF=2 & totally imbalanced network
> arch.
> >
> > Vnodes attempt to solve the problem of imbalanced rings by choosing so
> many tokens that it's improbable that the ring will be imbalanced.
>
> Storage/load distro = function(1st replica placement, other replica
> placement)
>
> vnode solves the balancing pb for 1st replica placement // so, yes, I
> agree with you, but for 1st replica placement only
>
> But NetworkTopologyStrategy (NTS) influences other (2+) replica placement
> => as NTS best behavior relies on token distro, and you have no control on
> tokens with vnodes, the best option I see with **vnode** is to use only one
> rack with NTS.
>
> Dominique
>
>
> -----Message d'origine-----
> De : jonathan.haddad@gmail.com [mailto:jonathan.haddad@gmail.com] De la
> part de Jonathan Haddad
> Envoyé : mardi 5 août 2014 18:04
> À : user@cassandra.apache.org
> Objet : Re: vnode and NetworkTopologyStrategy: not playing well together ?
>
> Yes, if you have only 1 machine in a rack then your cluster will be
> imbalanced. You're going to be able to dream up all sorts of weird failure
> cases when you choose a scenario like RF=2 & totally imbalanced network
> arch.
>
> Vnodes attempt to solve the problem of imbalanced rings by choosing so
> many tokens that it's improbable that the ring will be imbalanced.
>
>
>
> On Tue, Aug 5, 2014 at 8:57 AM, DE VITO Dominique <
> dominique.devito@thalesgroup.com> wrote:
> > First, thanks for your answer.
> >
> >> This is incorrect. Network Topology w/ Vnodes will be fine, assuming
> you've got RF= # of racks.
> >
> > IMHO, it's not a good enough condition.
> > Let's use an example with RF=2
> >
> > N1/rack_1 N2/rack_1 N3/rack_1 N4/rack_2
> >
> > Here, you have RF= # of racks
> > And due to NetworkTopologyStrategy, N4 will store *all* the cluster
> data, leading to a completely imbalanced cluster.
> >
> > IMHO, it happens when using nodes *or* vnodes.
> >
> > As well-balanced clusters with NetworkTopologyStrategy rely on carefully
> chosen token distribution/path along the ring *and* as tokens are
> randomly-generated with vnodes, my guess is that with vnodes and
> NetworkTopologyStrategy, it's better to define a single (logical) rack //
> due to "carefully chosen tokens" vs "randomly-generated token" clash.
> >
> > I don't see other options left.
> > Do you see other ones ?
> >
> > Regards,
> > Dominique
> >
> >
> >
> >
> > -----Message d'origine-----
> > De : jonathan.haddad@gmail.com [mailto:jonathan.haddad@gmail.com] De
> > la part de Jonathan Haddad Envoyé : mardi 5 août 2014 17:43 À :
> > user@cassandra.apache.org Objet : Re: vnode and
> > NetworkTopologyStrategy: not playing well together ?
> >
> > This is incorrect. Network Topology w/ Vnodes will be fine, assuming
> you've got RF= # of racks. For each token, replicas are chosen based on
> the strategy. Essentially, you could have a wild imbalance in token
> ownership, but it wouldn't matter because the replicas would be distributed
> across the rest of the machines.
> >
> > http://www.datastax.com/documentation/cassandra/2.0/cassandra/architec
> > ture/architectureDataDistributeReplication_c.html
> >
> > On Tue, Aug 5, 2014 at 8:19 AM, DE VITO Dominique <
> dominique.devito@thalesgroup.com> wrote:
> >> Hi,
> >>
> >>
> >>
> >> My understanding is that NetworkTopologyStrategy does NOT play well
> >> with vnodes, due to:
> >>
> >> · Vnode => tokens are (usually) randomly generated (AFAIK)
> >>
> >> · NetworkTopologyStrategy => required carefully choosen tokens
> for
> >> all nodes in order to not to get a VERY unbalanced ring like in
> >> https://issues.apache.org/jira/browse/CASSANDRA-3810
> >>
> >>
> >>
> >> When playing with vnodes, is the recommendation to define one rack
> >> for the entire cluster ?
> >>
> >>
> >>
> >> Thanks.
> >>
> >>
> >>
> >> Regards,
> >>
> >> Dominique
> >>
> >>
> >>
> >>
> >
> >
> >
> > --
> > Jon Haddad
> > http://www.rustyrazorblade.com
> > skype: rustyrazorblade
>
>
>
> --
> Jon Haddad
> http://www.rustyrazorblade.com
> skype: rustyrazorblade
>
RE: vnode and NetworkTopologyStrategy: not playing well together ?
Posted by DE VITO Dominique <do...@thalesgroup.com>.
> Jonathan wrote:
>
> Yes, if you have only 1 machine in a rack then your cluster will be imbalanced. You're going to be able to dream up all sorts of weird failure cases when you choose a scenario like RF=2 & totally imbalanced network arch.
>
> Vnodes attempt to solve the problem of imbalanced rings by choosing so many tokens that it's improbable that the ring will be imbalanced.
Storage/load distro = function(1st replica placement, other replica placement)
vnode solves the balancing pb for 1st replica placement // so, yes, I agree with you, but for 1st replica placement only
But NetworkTopologyStrategy (NTS) influences other (2+) replica placement => as NTS best behavior relies on token distro, and you have no control on tokens with vnodes, the best option I see with **vnode** is to use only one rack with NTS.
Dominique
-----Message d'origine-----
De : jonathan.haddad@gmail.com [mailto:jonathan.haddad@gmail.com] De la part de Jonathan Haddad
Envoyé : mardi 5 août 2014 18:04
À : user@cassandra.apache.org
Objet : Re: vnode and NetworkTopologyStrategy: not playing well together ?
Yes, if you have only 1 machine in a rack then your cluster will be imbalanced. You're going to be able to dream up all sorts of weird failure cases when you choose a scenario like RF=2 & totally imbalanced network arch.
Vnodes attempt to solve the problem of imbalanced rings by choosing so many tokens that it's improbable that the ring will be imbalanced.
On Tue, Aug 5, 2014 at 8:57 AM, DE VITO Dominique <do...@thalesgroup.com> wrote:
> First, thanks for your answer.
>
>> This is incorrect. Network Topology w/ Vnodes will be fine, assuming you've got RF= # of racks.
>
> IMHO, it's not a good enough condition.
> Let's use an example with RF=2
>
> N1/rack_1 N2/rack_1 N3/rack_1 N4/rack_2
>
> Here, you have RF= # of racks
> And due to NetworkTopologyStrategy, N4 will store *all* the cluster data, leading to a completely imbalanced cluster.
>
> IMHO, it happens when using nodes *or* vnodes.
>
> As well-balanced clusters with NetworkTopologyStrategy rely on carefully chosen token distribution/path along the ring *and* as tokens are randomly-generated with vnodes, my guess is that with vnodes and NetworkTopologyStrategy, it's better to define a single (logical) rack // due to "carefully chosen tokens" vs "randomly-generated token" clash.
>
> I don't see other options left.
> Do you see other ones ?
>
> Regards,
> Dominique
>
>
>
>
> -----Message d'origine-----
> De : jonathan.haddad@gmail.com [mailto:jonathan.haddad@gmail.com] De
> la part de Jonathan Haddad Envoyé : mardi 5 août 2014 17:43 À :
> user@cassandra.apache.org Objet : Re: vnode and
> NetworkTopologyStrategy: not playing well together ?
>
> This is incorrect. Network Topology w/ Vnodes will be fine, assuming you've got RF= # of racks. For each token, replicas are chosen based on the strategy. Essentially, you could have a wild imbalance in token ownership, but it wouldn't matter because the replicas would be distributed across the rest of the machines.
>
> http://www.datastax.com/documentation/cassandra/2.0/cassandra/architec
> ture/architectureDataDistributeReplication_c.html
>
> On Tue, Aug 5, 2014 at 8:19 AM, DE VITO Dominique <do...@thalesgroup.com> wrote:
>> Hi,
>>
>>
>>
>> My understanding is that NetworkTopologyStrategy does NOT play well
>> with vnodes, due to:
>>
>> · Vnode => tokens are (usually) randomly generated (AFAIK)
>>
>> · NetworkTopologyStrategy => required carefully choosen tokens for
>> all nodes in order to not to get a VERY unbalanced ring like in
>> https://issues.apache.org/jira/browse/CASSANDRA-3810
>>
>>
>>
>> When playing with vnodes, is the recommendation to define one rack
>> for the entire cluster ?
>>
>>
>>
>> Thanks.
>>
>>
>>
>> Regards,
>>
>> Dominique
>>
>>
>>
>>
>
>
>
> --
> Jon Haddad
> http://www.rustyrazorblade.com
> skype: rustyrazorblade
--
Jon Haddad
http://www.rustyrazorblade.com
skype: rustyrazorblade
Re: vnode and NetworkTopologyStrategy: not playing well together ?
Posted by Jonathan Haddad <jo...@jonhaddad.com>.
Yes, if you have only 1 machine in a rack then your cluster will be
imbalanced. You're going to be able to dream up all sorts of weird
failure cases when you choose a scenario like RF=2 & totally
imbalanced network arch.
Vnodes attempt to solve the problem of imbalanced rings by choosing so
many tokens that it's improbable that the ring will be imbalanced.
On Tue, Aug 5, 2014 at 8:57 AM, DE VITO Dominique
<do...@thalesgroup.com> wrote:
> First, thanks for your answer.
>
>> This is incorrect. Network Topology w/ Vnodes will be fine, assuming you've got RF= # of racks.
>
> IMHO, it's not a good enough condition.
> Let's use an example with RF=2
>
> N1/rack_1 N2/rack_1 N3/rack_1 N4/rack_2
>
> Here, you have RF= # of racks
> And due to NetworkTopologyStrategy, N4 will store *all* the cluster data, leading to a completely imbalanced cluster.
>
> IMHO, it happens when using nodes *or* vnodes.
>
> As well-balanced clusters with NetworkTopologyStrategy rely on carefully chosen token distribution/path along the ring *and* as tokens are randomly-generated with vnodes, my guess is that with vnodes and NetworkTopologyStrategy, it's better to define a single (logical) rack // due to "carefully chosen tokens" vs "randomly-generated token" clash.
>
> I don't see other options left.
> Do you see other ones ?
>
> Regards,
> Dominique
>
>
>
>
> -----Message d'origine-----
> De : jonathan.haddad@gmail.com [mailto:jonathan.haddad@gmail.com] De la part de Jonathan Haddad
> Envoyé : mardi 5 août 2014 17:43
> À : user@cassandra.apache.org
> Objet : Re: vnode and NetworkTopologyStrategy: not playing well together ?
>
> This is incorrect. Network Topology w/ Vnodes will be fine, assuming you've got RF= # of racks. For each token, replicas are chosen based on the strategy. Essentially, you could have a wild imbalance in token ownership, but it wouldn't matter because the replicas would be distributed across the rest of the machines.
>
> http://www.datastax.com/documentation/cassandra/2.0/cassandra/architecture/architectureDataDistributeReplication_c.html
>
> On Tue, Aug 5, 2014 at 8:19 AM, DE VITO Dominique <do...@thalesgroup.com> wrote:
>> Hi,
>>
>>
>>
>> My understanding is that NetworkTopologyStrategy does NOT play well
>> with vnodes, due to:
>>
>> · Vnode => tokens are (usually) randomly generated (AFAIK)
>>
>> · NetworkTopologyStrategy => required carefully choosen tokens for
>> all nodes in order to not to get a VERY unbalanced ring like in
>> https://issues.apache.org/jira/browse/CASSANDRA-3810
>>
>>
>>
>> When playing with vnodes, is the recommendation to define one rack for
>> the entire cluster ?
>>
>>
>>
>> Thanks.
>>
>>
>>
>> Regards,
>>
>> Dominique
>>
>>
>>
>>
>
>
>
> --
> Jon Haddad
> http://www.rustyrazorblade.com
> skype: rustyrazorblade
--
Jon Haddad
http://www.rustyrazorblade.com
skype: rustyrazorblade
RE: vnode and NetworkTopologyStrategy: not playing well together ?
Posted by DE VITO Dominique <do...@thalesgroup.com>.
First, thanks for your answer.
> This is incorrect. Network Topology w/ Vnodes will be fine, assuming you've got RF= # of racks.
IMHO, it's not a good enough condition.
Let's use an example with RF=2
N1/rack_1 N2/rack_1 N3/rack_1 N4/rack_2
Here, you have RF= # of racks
And due to NetworkTopologyStrategy, N4 will store *all* the cluster data, leading to a completely imbalanced cluster.
IMHO, it happens when using nodes *or* vnodes.
As well-balanced clusters with NetworkTopologyStrategy rely on carefully chosen token distribution/path along the ring *and* as tokens are randomly-generated with vnodes, my guess is that with vnodes and NetworkTopologyStrategy, it's better to define a single (logical) rack // due to "carefully chosen tokens" vs "randomly-generated token" clash.
I don't see other options left.
Do you see other ones ?
Regards,
Dominique
-----Message d'origine-----
De : jonathan.haddad@gmail.com [mailto:jonathan.haddad@gmail.com] De la part de Jonathan Haddad
Envoyé : mardi 5 août 2014 17:43
À : user@cassandra.apache.org
Objet : Re: vnode and NetworkTopologyStrategy: not playing well together ?
This is incorrect. Network Topology w/ Vnodes will be fine, assuming you've got RF= # of racks. For each token, replicas are chosen based on the strategy. Essentially, you could have a wild imbalance in token ownership, but it wouldn't matter because the replicas would be distributed across the rest of the machines.
http://www.datastax.com/documentation/cassandra/2.0/cassandra/architecture/architectureDataDistributeReplication_c.html
On Tue, Aug 5, 2014 at 8:19 AM, DE VITO Dominique <do...@thalesgroup.com> wrote:
> Hi,
>
>
>
> My understanding is that NetworkTopologyStrategy does NOT play well
> with vnodes, due to:
>
> · Vnode => tokens are (usually) randomly generated (AFAIK)
>
> · NetworkTopologyStrategy => required carefully choosen tokens for
> all nodes in order to not to get a VERY unbalanced ring like in
> https://issues.apache.org/jira/browse/CASSANDRA-3810
>
>
>
> When playing with vnodes, is the recommendation to define one rack for
> the entire cluster ?
>
>
>
> Thanks.
>
>
>
> Regards,
>
> Dominique
>
>
>
>
--
Jon Haddad
http://www.rustyrazorblade.com
skype: rustyrazorblade
Re: vnode and NetworkTopologyStrategy: not playing well together ?
Posted by Jonathan Haddad <jo...@jonhaddad.com>.
* When I say wild imbalance, I do not mean all tokens on 1 node in the
cluster, I really should have said slightly imbalanced
On Tue, Aug 5, 2014 at 8:43 AM, Jonathan Haddad <jo...@jonhaddad.com> wrote:
> This is incorrect. Network Topology w/ Vnodes will be fine, assuming
> you've got RF= # of racks. For each token, replicas are chosen based
> on the strategy. Essentially, you could have a wild imbalance in
> token ownership, but it wouldn't matter because the replicas would be
> distributed across the rest of the machines.
>
> http://www.datastax.com/documentation/cassandra/2.0/cassandra/architecture/architectureDataDistributeReplication_c.html
>
> On Tue, Aug 5, 2014 at 8:19 AM, DE VITO Dominique
> <do...@thalesgroup.com> wrote:
>> Hi,
>>
>>
>>
>> My understanding is that NetworkTopologyStrategy does NOT play well with
>> vnodes, due to:
>>
>> · Vnode => tokens are (usually) randomly generated (AFAIK)
>>
>> · NetworkTopologyStrategy => required carefully choosen tokens for
>> all nodes in order to not to get a VERY unbalanced ring like in
>> https://issues.apache.org/jira/browse/CASSANDRA-3810
>>
>>
>>
>> When playing with vnodes, is the recommendation to define one rack for the
>> entire cluster ?
>>
>>
>>
>> Thanks.
>>
>>
>>
>> Regards,
>>
>> Dominique
>>
>>
>>
>>
>
>
>
> --
> Jon Haddad
> http://www.rustyrazorblade.com
> skype: rustyrazorblade
--
Jon Haddad
http://www.rustyrazorblade.com
skype: rustyrazorblade
Re: vnode and NetworkTopologyStrategy: not playing well together ?
Posted by Jonathan Haddad <jo...@jonhaddad.com>.
This is incorrect. Network Topology w/ Vnodes will be fine, assuming
you've got RF= # of racks. For each token, replicas are chosen based
on the strategy. Essentially, you could have a wild imbalance in
token ownership, but it wouldn't matter because the replicas would be
distributed across the rest of the machines.
http://www.datastax.com/documentation/cassandra/2.0/cassandra/architecture/architectureDataDistributeReplication_c.html
On Tue, Aug 5, 2014 at 8:19 AM, DE VITO Dominique
<do...@thalesgroup.com> wrote:
> Hi,
>
>
>
> My understanding is that NetworkTopologyStrategy does NOT play well with
> vnodes, due to:
>
> · Vnode => tokens are (usually) randomly generated (AFAIK)
>
> · NetworkTopologyStrategy => required carefully choosen tokens for
> all nodes in order to not to get a VERY unbalanced ring like in
> https://issues.apache.org/jira/browse/CASSANDRA-3810
>
>
>
> When playing with vnodes, is the recommendation to define one rack for the
> entire cluster ?
>
>
>
> Thanks.
>
>
>
> Regards,
>
> Dominique
>
>
>
>
--
Jon Haddad
http://www.rustyrazorblade.com
skype: rustyrazorblade