cassandra scalability

hey there, i'm trying to scale casandra cluster with openstack. But i'm seeing strange behavior when there is a scaleup (new node is added) scaledown (one node is removed). (don't worry the seeds are stable). I start my cluster with 2 machines, one seed and one server, then create the database

Re: cassandra scalability

at the biginning it looks like this: [root@demo-server-seed-k6g62qr57nok ~]# nodetool status Datacenter: DC1 === Status=Up/Down |/ State=Normal/Leaving/Joining/Moving -- Address Load Tokens OwnsHost ID Rack UN 40.0.0.208 128.73 KB 248

RE: cassandra scalability

Could you provide the result of : - nodetool status - nodetool status YOURKEYSPACE

Re: cassandra scalability

when there's a scaledown action, i make sure to decommission the node before. but still, I don't understand why I'm having this behaviour. is it normal. what do you do normally to remove a node? is it related to tokens? i'm affecting to each of my node a different token based on there ip address

Re: Is Cassandra really Strong consistency?

""It you need strong consistency and don't mind lower transaction rate, you're better off with base"" I wish you can explain more how this statment relate to the my post? Regards,

RE: cassandra scalability

Please, don't mail me directly I read your answer, but I cannot help anymore And answering with "Sorry, I can't help" is pointless :) Wait for the community to answer De : ICHIBA Sara [mailto:ichi.s...@gmail.com] Envoyé : Monday, September 07, 2015 11:34 AM À : user@cassandra.apache.org Objet 

Re: Is Cassandra really Strong consistency?

The condition you bring up is a misconfigured cluster period, and no matter how you look at it, that's the case. In other words, the scenario you're bringing up does not get to the heart of the matter of Cassandra having "Strong Consistency" or not, your example I'm sorry to say fails in this

Re: Is Cassandra really Strong consistency?

Yes, you are right, I should not have linked my scenario with Strong consistency. Thank you Ibrahim On Mon, Sep 7, 2015 at 2:01 PM, Ryan Svihla wrote: > The condition you bring up is a misconfigured cluster period, and no > matter how you look at it, that's the case. In

Re: cassandra scalability

Thank you all for your answers. @Alain: Can you detail actions performed, >>like how you load data >>>i have a haproxy in front of my cassandra database, so i'm sure that my application queries each time a different coordinator >>what scaleup / scaledown are and precise if you let it

Re: cassandra scalability

I think I know where my problem is coming from. I took a look at the log of cassandra on each node and I saw something related to bootstrap. it says that the node is a seed so there will be no bootstraping. Actually I made a mistake. in the cassandra.yaml file each node have two ips as seeds. the

RE: Effect of adding/removing nodes from cassandra

Hi, Could you show us how you measure CPU & network? Just to be sure we're not missing something obvious Thanks, De : Alain RODRIGUEZ [mailto:arodr...@gmail.com] Envoyé : Monday, September 07, 2015 5:19 PM À : user@cassandra.apache.org Objet : Re: Effect of adding/removing nodes from

Re: cassandra scalability

Glad to hear that. About the Proxy Putting an HA proxy in front of Cassandra is an anti-pattern as you create a single point of failure. You can multiply them, but why would you do that anyway when most (all ?) of the modern Cassandra clients handle this for you through TokenAware / RoundRobin

Re: Convert joins in RDBMS to Cassandra

The normal approach is denormalization to a materialized view (the traditional thinking of it not the new 3.0 feature coming out), which is also true of using an RBMS at scale (joins across all data sets get expensive once you start having to shard across different servers). The simplistic idea

Re: Data Size on each node

Huge differences in ability to handle compaction and read contention. I've taken spindle servers struggling at 7k tps for the cluster with 9 node data centers (stupidly big writes, not my app) to doing that per node just by swapping out to SSD. This says nothing about the 100x change in latency on

Re: cassandra scalability

Hi Sara, Can you detail actions performed, like how you load data, what scaleup / scaledown are and precise if you let it decommission fully (streams finished, node removed from nodetool status) etc ? This would help us to help you :). Also, what happens if you query using "CONSISTENCY

Re: cassandra scalability

If that's what tracing is telling you then it's fine and just a product of data distribution (note your token count isn't identical anyway). If you're doing cl one queries directly against particular nodes and getting different results it sounds like dropped mutations, streaming errors and or

Re: How to prevent queries being routed to new DC?

What's your keyspace replication strategy? On Thu, Sep 3, 2015 at 3:16 PM Tom van den Berge wrote: > Thanks for your help so far! > > I have some problems trying to understand the jira mentioned by Rob :( > > I'm currently trying to set up the first node in the new DC

Re: Some love for multi-partition LWT?

Multi partitions LWT is not supported currently on purpose. To support it, we would have to emulate a distributed lock which is pretty bad for performance. On Mon, Sep 7, 2015 at 10:38 PM, Marek Lewandowski < marekmlewandow...@gmail.com> wrote: > Hello there, > > would you be interested in

Re: Querying on multiple columns

That is the state of data modeling with 2.1 and it's worked quite well for a lot of people (especially for those using batches or streaming to maintain the different views of the same data). However, you should be interested in the upcoming Materialized Views in 3.0

Re: How to prevent queries being routed to new DC?

Hi Tom, While reading data ( even at CL LOCAL_QUORUM), if data in different nodes required to meet CL in your local cluster doesnt match, data will be read from remote dc for read repair if read_repair_chance is not 0. Imp points: 1.If you are reading and writing at local_quorum you can set

Re: Is it possible to bootstrap the 1st node of a new DC?

Hi Christian, No, I never tried survey mode. I didn't know it until now, but form the info I was able to find it looks like it is meant for a different purpose. Maybe it can be used to bootstrap a new DC, though. On the other hand, the auto_bootstrap=false + rebuild scenario seems to be designed

Re: Is it possible to bootstrap the 1st node of a new DC?

Hi Tom, "one drawback: the node joins the cluster as soon as the bootstrapping begins." I am not sure I understand this correctly. It will get tokens, but not load data if you combine it with autobootstrap=false. How I see it: You should be able to start all the new nodes in the new DC with

Re: How to prevent queries being routed to new DC?

NetworkTopologyStrategy On Mon, Sep 7, 2015 at 4:39 PM, Ryan Svihla wrote: > What's your keyspace replication strategy? > > On Thu, Sep 3, 2015 at 3:16 PM Tom van den Berge < > tom.vandenbe...@gmail.com> wrote: > >> Thanks for your help so far! >> >> I have some problems

Re: Is it possible to bootstrap the 1st node of a new DC?

Running nodetool rebuild on a node that was started with join_ring=false does not work, unfortunately. The nodetool command returns immediately, after a message appears in the log that the streaming of data has started. After that, nothing happens. Tom On Fri, Sep 12, 2014 at 5:47 PM, Robert

Re: Is it possible to bootstrap the 1st node of a new DC?

Hi Tom, this sounds very much like my thread: "auto_bootstrap=false broken?" Did you try booting the new node with survey-mode? I wanted to try this, but I am waiting for 2.0.17 to come out (survey mode is broken in earlier versions). Imho survey mode is what you (and me too) want: start a node,

Re: Is Cassandra really Strong consistency?

Ok, With LWT, I am completely understand that it will achieve total order/linearizability, therefore above scenario cannot occur. However, when you said "the scenario will occur if your clocks are not sync’d". This is ambiguous statement. Because both client and server sides are likely to

Re: Is Cassandra really Strong consistency?

It you need strong consistency and don't mind lower transaction rate, you're better off with base Sent from my iPhone > On Sep 7, 2015, at 5:55 AM, ibrahim El-sanosi > wrote: > > Ok, > > > > With LWT, I am completely understand that it will achieve total >

Some love for multi-partition LWT?

Hello there, would you be interested in having multi-partition support for lightweight transactions in order words to have ability to express something like: INSERT INTO … IF NOT EXISTS AND UPDATE … IF EXISTS AND UPDATE … IF colX = ‘xyz’ where each statement refers to a row living potentially

Re: Order By limitation or bug?

Thanks. Based on what I know about the architecture, it seems like it should be pretty easy to support. Thanks for the confirmation and the ticket. On Sep 4, 2015, at 3:30 PM, Tyler Hobbs > wrote: This query would be reasonable to support, so I've