How to remove obsolete error message in Datastax Opscenter?

Good morning, unfortunately my last rolling restart of our Cassandra cluster issued from OpsCenter (5.0.2) failed. No big deal, but since then OpsCenter is showing an error message at the top of its screen: Error restarting cluster: Timed out waiting for Cassandra to start.. Does anybody know

Re: High GC activity on node with 4TB on data

- number of tombstones - how can I reliably find it out? https://github.com/spotify/cassandra-opstools https://github.com/cloudian/support-tools If not getting much compression it may be worth trying to disable it, it may contribute but its very unlikely that its the cause of the gc pressure

about insert into table with IF NOT EXISTS error

Hi: I setup one node cassandra server, and using node.js driver cql to query db. But, when insert into table with IF NOT EXISTS statement, it report error as below: :ResponseError: Cannot achieve consistency level QUORUM And, I try set nodejs cql query with consistency to ONE, still see

nodetool status shows large numbers of up nodes are down

Hi, We have a two-dc cluster with 21 nodes and 27 nodes in each DC. Over the past few months, we have seen nodetool status marks 4-8 nodes down while they are actually functioning. Particularly today we noticed that running nodetool status on some nodes shows higher number of nodes are down than

Re[2]: Question about adding nodes to a cluster

Sorry, No - you are not doing it wrong ^) Yes, Cassandra partitioner is based on hash ring. Doubling number of nodes is the best cluster exctending policy I've ever seen, because it's zero-overhead. Hashring - you get MD5 max (2^128-1), divide it by number of nodes (partitions) getting N

Re: Question about adding nodes to a cluster

On Mon, Feb 9, 2015 at 4:59 PM, Seth Edwards s...@pubnub.com wrote: We are choosing to double our cluster from six to twelve. I ran the token generator. Based on what I read in the documentation, I expected to see the same first six tokens and six new tokens. Instead I see almost the same

Re: nodetool status shows large numbers of up nodes are down

Hi Cheng, Are all machines configured with NTP and all clocks in sync? If that is not the case do it. If your clocks are not in sync it causes some weird issues like the ones you see, but also schema disagreements and in some cases corrupted data. Regards, Regards, Carlos Juzarte Rolo

Re: Question about adding nodes to a cluster

I see what you are saying. So basically take whatever existing token I have and divide it by 2, give or take a couple of tokens? On Mon, Feb 9, 2015 at 5:17 PM, Robert Coli rc...@eventbrite.com wrote: On Mon, Feb 9, 2015 at 4:59 PM, Seth Edwards s...@pubnub.com wrote: We are choosing to

Re: Adding more nodes causes performance problem

Can you copy and example of your read and write queries? Are they both degrading in the same way performance wise? On Mon, Feb 9, 2015 at 8:39 PM, Laing, Michael michael.la...@nytimes.com wrote: Use token-awareness so you don't have as much coordinator overhead. ml On Mon, Feb 9, 2015 at

Re: High GC activity on node with 4TB on data

Hi all, thank you all for the info. To answer the questions: - we have 2 DCs with 5 nodes in each, each node has 256G of memory, 24x1T drives, 2x Xeon CPU - there are multiple cassandra instances running for different project. The node itself is powerful enough. - there 2 keyspaces, one with 3

Re: How to remove obsolete error message in Datastax Opscenter?

To clarify what Chris said, restarting opscenter will remove the notification, but we also have a bug filed to make that behavior a little better and allow dismissing that notification without a restart. Thanks for reporting the issue! -Nick On Mon, Feb 9, 2015 at 9:00 AM, Chris Lohfink

Re: Fastest way to map/parallel read all values in a table?

I had considered using spark for this but: 1. we tried to deploy spark only to find out that it was missing a number of key things we need. 2. our app needs to shut down to release threads and resources. Spark doesn’t have support for this so all the workers would have stale thread leaking

Question about adding nodes to a cluster

I am on Cassandra 1.2.19 and I am following the documentation for adding existing nodes to a cluster http://www.datastax.com/docs/1.1/cluster_management#adding-capacity-to-an-existing-cluster . We are choosing to double our cluster from six to twelve. I ran the token generator. Based on what I

Re: Question about adding nodes to a cluster

Yes, Cassandra partitioner is based on hash ring. Doubling number of nodes is the best cluster exctending policy I've ever seen, because it's zero-overhead. Hashring - you get MD5 max (2^128-1), divide it by number of nodes (partitions) getting N points and then evenly distribute them across

Re: about insert into table with IF NOT EXISTS error

Tom, this question would have better chances to be answered on the Node.js driver mailing list https://groups.google.com/a/lists.datastax.com/forum/#!forum/nodejs-driver-user On Mon, Feb 9, 2015 at 5:38 PM, tom zs68j...@gmail.com wrote: Hi: I setup one node cassandra server, and using

Re: about insert into table with IF NOT EXISTS error

How about delete the previous inserted lines? Then, insert it again? *Best Regards！* *Chao Yan--**My twitter：Andy Yan @yanchao727 https://twitter.com/yanchao727* *My Weibo：http://weibo.com/herewearenow http://weibo.com/herewearenow--* 2015-02-10 9:52 GMT+08:00 Alex

Re:Fastest way to map/parallel read all values in a table?

Just for the record, I was doing the exact same thing in an internal application in the start up I used to work. We have had the need of writing custom code process in parallel all rows of a column family. Normally we would use Spark for the job, but in our case the logic was a little more

Re:Adding more nodes causes performance problem

AFAIK, if you were using RF 3 in a 3 node cluster, so all your nodes had all your data. When the number of nodes started to grow, this assumption stopped being true. I think Cassandra will scale linearly from 9 nodes on, but comparing a situation where all your nodes hold all your data is not

Re: How to remove obsolete error message in Datastax Opscenter?

Stop using opscenter? :) Sorry, couldnt resist... -- Colin Clark +1 612 859 6129 Skype colin.p.clark On Feb 9, 2015, at 3:01 AM, Björn Hachmann bjoern.hachm...@metrigo.de wrote: Good morning, unfortunately my last rolling restart of our Cassandra cluster issued from OpsCenter (5.0.2)

Re: Adding more nodes causes performance problem

Use token-awareness so you don't have as much coordinator overhead. ml On Mon, Feb 9, 2015 at 5:32 AM, Marcelo Valle (BLOOMBERG/ LONDON) mvallemil...@bloomberg.net wrote: AFAIK, if you were using RF 3 in a 3 node cluster, so all your nodes had all your data. When the number of nodes started

Re: How to remove obsolete error message in Datastax Opscenter?

Restarting opscenter service will get rid of it. Chris On Mon, Feb 9, 2015 at 3:01 AM, Björn Hachmann bjoern.hachm...@metrigo.de wrote: Good morning, unfortunately my last rolling restart of our Cassandra cluster issued from OpsCenter (5.0.2) failed. No big deal, but since then OpsCenter is

Re: Fastest way to map/parallel read all values in a table?

Depending on whether you have deletes/updates, if this is an ad-hoc thing, you might want to just read the ss tables directly. On Feb 9, 2015, at 12:56 PM, Kevin Burton bur...@spinn3r.com wrote: I had considered using spark for this but: 1. we tried to deploy spark only to find out that