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Posted to user@cassandra.apache.org by Andrey Ilinykh <ai...@gmail.com> on 2012/10/14 08:19:58 UTC
what happens while node is bootstrapping?
Hello, everybody!
I'd like to clarify a bootstrapping process. As far as I understand,
bootstrapping node starts to accept writes immediately. What about
reads?
Bootstrapping node doesn't have all information, only replica nodes
have. Does it mean read operations with CL ALL may fail during
bootstrapping process?
Thank you,
Andrey
RE: what happens while node is bootstrapping?
Posted by DE VITO Dominique <do...@thalesgroup.com>.
> > De : Tyler Hobbs [mailto:tyler@datastax.com]
> > Envoyé : mardi 16 octobre 2012 17:04
> > À : user@cassandra.apache.org
> > Objet : Re: what happens while node is bootstrapping?
> >
> > On Mon, Oct 15, 2012 at 3:50 PM, Andrey Ilinykh <ai...@gmail.com> wrote:
> > Does it mean that during bootstrapping process only replicas serve
> > read requests for new node range? In other words, replication factor
> > is RF-1?
>
> No. The bootstrapping node will writes for its new range while bootstrapping as consistency optimization (more or less), but does not contribute to the replication factor or consistency level; all of the original replicas for that range still receive writes, serve reads, and are the nodes that count for consistency level. Basically, the bootstrapping node has no effect on the existing replicas in terms of RF or CL until the bootstrap completes.
>
> --
> Tyler Hobbs
> DataStax
For the purposes of the consistency optimization, I would have written that the (new) node bootstrapping should receive writes, but also its own replicas (!).
In case of SimpleStrategy, it's obvious that the new node replicas are included into the original replicas. So, it's valid to say "The bootstrapping node will writes for its new range while bootstrapping as consistency optimization" without mentionning the new node replicas.
In case of NetworkTopologyStrategy, after having played with some examples to support my following claim, I suspect the new node replicas are also included into the original replicas. So, I am inclined to say it's valid too to say "The bootstrapping node will writes for its new range while bootstrapping as consistency optimization" without mentionning the new node replicas.
1) In case of NetworkTopologyStrategy, for a bootstrap, is it correct to say that the new node replicas are *always* included into the original replicas ?
(I think Cassandra dev have already proved it).
2) in case of bootstrapping multiple nodes at the same time, the replicas of a new node are *not*always included into the original replicas.
Is it a pb for Cassandra (and then, do we need to bootstrap nodes one by one ?), or is Cassandra able to detect multiple nodes are bootstrapping and to deal with it to fetch data on the right nodes ?
Thanks.
Regards,
Dominique
Re: what happens while node is bootstrapping?
Posted by Michael Kjellman <mk...@barracuda.com>.
Correct.
Also, there is a new feature in 1.1+ that lets you play with live traffic
on new nodes before they actually join the ring
http://www.datastax.com/dev/blog/whats-new-in-cassandra-1-1-live-traffic-sa
mpling
On 10/16/12 9:42 AM, "Andrey Ilinykh" <ai...@gmail.com> wrote:
>>
>>
>> No. The bootstrapping node will writes for its new range while
>> bootstrapping as consistency optimization (more or less), but does not
>> contribute to the replication factor or consistency level; all of the
>> original replicas for that range still receive writes, serve reads, and
>>are
>> the nodes that count for consistency level. Basically, the
>>bootstrapping
>> node has no effect on the existing replicas in terms of RF or CL until
>>the
>> bootstrap completes.
>>
>I see. So, if I add new nodes to increase number of writes my cluster
>can handle I will not see any improvement until bootstrap process
>finished, which may take hours. Is it correct?
>
>Thank you,
> Andrey
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Re: what happens while node is bootstrapping?
Posted by Andrey Ilinykh <ai...@gmail.com>.
>
>
> No. The bootstrapping node will writes for its new range while
> bootstrapping as consistency optimization (more or less), but does not
> contribute to the replication factor or consistency level; all of the
> original replicas for that range still receive writes, serve reads, and are
> the nodes that count for consistency level. Basically, the bootstrapping
> node has no effect on the existing replicas in terms of RF or CL until the
> bootstrap completes.
>
I see. So, if I add new nodes to increase number of writes my cluster
can handle I will not see any improvement until bootstrap process
finished, which may take hours. Is it correct?
Thank you,
Andrey
Re: what happens while node is bootstrapping?
Posted by Tyler Hobbs <ty...@datastax.com>.
On Mon, Oct 15, 2012 at 3:50 PM, Andrey Ilinykh <ai...@gmail.com> wrote:
> Does it mean that during bootstrapping process only replicas serve
> read requests for new node range? In other words, replication factor
> is RF-1?
>
No. The bootstrapping node will writes for its new range while
bootstrapping as consistency optimization (more or less), but does not
contribute to the replication factor or consistency level; all of the
original replicas for that range still receive writes, serve reads, and are
the nodes that count for consistency level. Basically, the bootstrapping
node has no effect on the existing replicas in terms of RF or CL until the
bootstrap completes.
--
Tyler Hobbs
DataStax <http://datastax.com/>
Re: what happens while node is bootstrapping?
Posted by Will Martin <wi...@voodoolunchbox.com>.
The Kafka team has resources for tuning the socket buffer sizes. It seems that with a reasonable amount of memory, there should be an activity queue waiting after the bootstrap process. Is this checked? Is it feasible to pick it up? Is this already done?
On Oct 15, 2012, at 4:50 PM, Andrey Ilinykh wrote:
> Does it mean that during bootstrapping process only replicas serve
> read requests for new node range? In other words, replication factor
> is RF-1?
>
> On Mon, Oct 15, 2012 at 12:20 PM, John Lewis <le...@gmail.com> wrote:
>> Bootstrapping nodes do not handle reads requests until the bootstrap process is complete.
>>
>> JLewis
>>
>> On Oct 13, 2012, at 11:19 PM, Andrey Ilinykh <ai...@gmail.com> wrote:
>>
>>> Hello, everybody!
>>> I'd like to clarify a bootstrapping process. As far as I understand,
>>> bootstrapping node starts to accept writes immediately. What about
>>> reads?
>>> Bootstrapping node doesn't have all information, only replica nodes
>>> have. Does it mean read operations with CL ALL may fail during
>>> bootstrapping process?
>>>
>>> Thank you,
>>> Andrey
>>
Re: what happens while node is bootstrapping?
Posted by Andrey Ilinykh <ai...@gmail.com>.
Does it mean that during bootstrapping process only replicas serve
read requests for new node range? In other words, replication factor
is RF-1?
On Mon, Oct 15, 2012 at 12:20 PM, John Lewis <le...@gmail.com> wrote:
> Bootstrapping nodes do not handle reads requests until the bootstrap process is complete.
>
> JLewis
>
> On Oct 13, 2012, at 11:19 PM, Andrey Ilinykh <ai...@gmail.com> wrote:
>
>> Hello, everybody!
>> I'd like to clarify a bootstrapping process. As far as I understand,
>> bootstrapping node starts to accept writes immediately. What about
>> reads?
>> Bootstrapping node doesn't have all information, only replica nodes
>> have. Does it mean read operations with CL ALL may fail during
>> bootstrapping process?
>>
>> Thank you,
>> Andrey
>
RE: what happens while node is bootstrapping?
Posted by Jaipal Deswal <Ja...@wizecommerce.com>.
According to my experience if bootstrap is running on already Live cluster node (and dead from sometime) then it start serving read during bootstrap process also but if bootstrap is running on new node (which is joining cluster first time) then read requests will not go to this node until bootstrap completes
-----Original Message-----
From: John Lewis [mailto:lewilists@gmail.com]
Sent: 16 October 2012 00:51
To: user@cassandra.apache.org
Subject: Re: what happens while node is bootstrapping?
Bootstrapping nodes do not handle reads requests until the bootstrap process is complete.
JLewis
On Oct 13, 2012, at 11:19 PM, Andrey Ilinykh <ai...@gmail.com> wrote:
> Hello, everybody!
> I'd like to clarify a bootstrapping process. As far as I understand,
> bootstrapping node starts to accept writes immediately. What about
> reads?
> Bootstrapping node doesn't have all information, only replica nodes
> have. Does it mean read operations with CL ALL may fail during
> bootstrapping process?
>
> Thank you,
> Andrey
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Re: what happens while node is bootstrapping?
Posted by John Lewis <le...@gmail.com>.
Bootstrapping nodes do not handle reads requests until the bootstrap process is complete.
JLewis
On Oct 13, 2012, at 11:19 PM, Andrey Ilinykh <ai...@gmail.com> wrote:
> Hello, everybody!
> I'd like to clarify a bootstrapping process. As far as I understand,
> bootstrapping node starts to accept writes immediately. What about
> reads?
> Bootstrapping node doesn't have all information, only replica nodes
> have. Does it mean read operations with CL ALL may fail during
> bootstrapping process?
>
> Thank you,
> Andrey