Apache Cassandra is an open source distributed database management system.

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7
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2answers
383 views

Configuring Cassandra for consistency across multiple datacenters

Currently we run a 4-node Cassandra ring in each of two datacenters. We would like to rebuild them into a single 8-node ring. All else being equal we would really like to have consistent reads, so we ...
4
votes
3answers
289 views

Cassandra - hardware planning

Briefly: if I have 5 Tb of data and want to deploy this on 5 cassandra servers - does each machine need to have 5 Tb of disk space for data (not counting log space)? From the docs it sounds like at ...
4
votes
1answer
1k views

What is the best solution for backing up data in Cassandra? [closed]

What is the best solution for backing up data in Cassandra?
3
votes
6answers
607 views

How to achieve zero down time

For an application we want to achieve zero database and application down time using Active Active configuration. Our dB is Oracle Following are my questions: How can we achieve active active ...
3
votes
1answer
931 views

Unclosed TCP connections in CLOSE_WAIT for various processes

I have cluster of several machines connected on 10GBE network (NICs are Intel 82599EB 10GBE SFI/SFP+) running under Debian 6.0 and faced with problem of hung up TCP connections in CLOSE_WAIT state. I ...
2
votes
2answers
3k views

How can I get Cassandra to automatically rebalance?

I am looking at a cassandra cluster, but the administration effort seems to be quite high. Is there any way I can configure Cassandra to rebalance nodes automically as new machines are added, some are ...
2
votes
1answer
128 views

Cassandra EC2 slow response time

I have been developing with Cassandra locally for a while and response times on queries are in the region of 50ms. I have set up a 5 node EC2 cluster from the cassandra community ami, everything went ...
2
votes
1answer
83 views

DataStax OpsCenter 3.2.2 fails to start properly when storing collection data on different server

I'm trying to run OpsCenter 3.2.2 (enterprise edition) using a separate cluster used for storing the collection data. I specify the [storage_cassandra] tag in the cluster configuration. When starting ...
2
votes
1answer
40 views

Cannot generate cluster reports in OpsCenter.

I cannot generate a cluster report in OpsCenter. The server and clients are running on CentOS 5.9, 64bit. Software versions: opscenter-3.2.2-1 opscenter-agent-3.2.2-1 Here is the error reported ...
2
votes
1answer
51 views

I'm moving nodes around on a Cassandra cluster, and seeing “Back pressure disabled!” in the logs

I'm moving nodes around on a Cassandra cluster, and seeing Back pressure disabled! in the log. I'm also seeing (around a minute earlier) Back pressure enabled with average index queue size: 1106. ...
2
votes
2answers
272 views

Dynamically changing one-node Cassandra cluster to two nodes

So I have an application that will be very dormant most of the time but will need high-bursting a few days out of the month. Since we are deploying on EC2 I would like to keep only one Cassandra ...
2
votes
1answer
112 views

How do I automatically add Cassandra nodes to Windows DNS?

I'm working on building a new Cassandra cluster and I'd like to create a DNS record that will hold the IP addresses of all of the nodes. I build all of my servers in the cloud and they automatically ...
2
votes
1answer
115 views

Can I run multiple nodes of Cassandra on my mac without a virtual machine for each?

You can see in the doco here that setting up each instance of Cassandra requires a new 'node'. My question is - to run a cluster with multiple nodes of Cassandra on my Mac (Running Mavericks) - do I ...
2
votes
1answer
492 views

Many concurrent Cassandra database connections thru SSH tunnel

I have an application that uses the PyCassa Cassandra client to open many concurrent connections to a Cassandra server. When I run the client application locally on the database server, it works. ...
1
vote
3answers
1k views

Can't upgrade my Ubuntu server, it gets stuck on openjdk-6-jre-headless

I am using Ubuntu Server. When I do: apt-get upgrade it gets stuck on: Setting up openjdk-6-jre-headless (6b20-1.9.7-0ubuntu1) ... Why? And what can I do to stop it? I tried removing it with ...
1
vote
1answer
46 views

How can I view the cache-hit ratio for a single column-family in Cassandra?

I've enabled row-caching in for one of my column-families in Cassandra and I'l like to view the cache-hit ratio? I can see the cache-hit ration metric in Cassandra's OspCenter but it seems to show me ...
1
vote
1answer
240 views

“Cannot bind to port” enabling Cassandra client encryption

I'm running Cassandra 1.2 with a three-node cluster, on Debian 7. The cluster is working fine. But I want to enable encryption for clients, as documented here: ...
1
vote
1answer
187 views

How to run datastax opscenter behind nginx

I would like to run datastax cassandra opscenter behind Nginx. But it keeps adding opscenter port (8888 by default) to all urls. Is there a config setting to disable that or something? Here is my ...
1
vote
2answers
69 views

startup cassandra layout

We've got a relatively low-traffic site (~1K pageviews/day) hosted on a single server, and expect it to grow significantly over the next few years. I'm thinking of moving over to Rackspace ...
1
vote
1answer
722 views

Unable to compile thrift on ubuntu

I am trying to install cassandra and thrift in my PC. I have successfully installed cassandra. But while making (using "make" command) thrift I am getting the error below: ............... ...
1
vote
1answer
508 views

cassandra node discovery

I just set up a 3 node system with ip addresses "192.168.0.101", "192.168.0.102", "192.168.0.103". I have set the seeds value on the configuration of all three machines as seeds: ...
1
vote
2answers
28 views

EC2 Attach Instance Store on Start

I'm lunching an instance to host a Cassandra node and i'm testing some shutdown and startup scripts. The instance was lunched from the datastax PV AMI 'ami-8932ccfe'. I added 8GB of SSD EBS storage ...
1
vote
1answer
220 views

Apache Cassandra Split Brain

First of all, apologies if this has been asked before, I cannot find an answer on Google or StackExchange. Is it possible to put Apache Cassandra into a split-brain scenario where a network ...
1
vote
1answer
633 views

DataStax Enterprise server won't start: dse dead but pid file exists

When I launch it with sudo /etc/init.d/dse start it seems to work. It returns: Starting DSE daemon dse DSE daemon starting with Hadoop and Solr disabled (edit /etc/default/dse to enable) But when I ...
1
vote
1answer
348 views

Reconfiguring data directories in an existing Cassandra node

I'm currently running a very simple single-node Cassandra box with the data files on a single disk. I'm about to add a couple of SSDs to the box and intend to add each SSD as another data directory to ...
1
vote
1answer
323 views

Processing pre-existing log files with Flume

I have a large set of log files that I need to extract data from. Is it possible to use Flume to read these files and dump them into an HDFS (Cassandra, or another data source) which I can then ...
1
vote
1answer
2k views

Cannot connect to my Cassandra

My Cassandra used to work with no problems. I was able to connect with no problems but now for some reason it doesn't work anymore. [default@unknown] connect localhost/9160; Exception connecting to ...
1
vote
1answer
204 views

IP address resolution in Cassandra MultiDC setup

We have a scenario for which we are considering using apache Cassandra for deployment for our data storage needs.The setup is to be spread across multiple data centers in different regions(physical ...
1
vote
1answer
342 views

Unable to connect to cassandra when using the AllowAllAuthenticator

I installed cassandra on a VM running Ubuntu Server 10.10. cassandra login failure with org.apache.cassandra.auth.AllowAllAuthenticator but I always receive the following error message: Login ...
1
vote
1answer
688 views

Cassandra on Linode: Dark magic isn't working

Yes, I realize I'm crossing the streams by running Cassandra on Linode. Yes, I know it would be better to run it on Rackspace or Amazon, but that's immaterial right now. Basically, I've got a Private ...
1
vote
1answer
614 views

Cassandra nodes in multiple data centers

http://www.cs.cornell.edu/projects/ladis2009/papers/lakshman-ladis2009.pdf : "Cassandra is configured such that each row is replicated across multiple data centers." So in that case is it good to ...
1
vote
0answers
60 views

Datastax Opscenter Agent installation is broken re: log4j

I am trying to install Opscenter, and datastax agent on our Cassandra cluster. When I start the datastax-agent, I am getting this error: log4j:WARN No appenders could be found for logger ...
1
vote
1answer
76 views

Opscenter 4.1 can't add cluster

When trying to add an existing cluster to Opscenter via the 'add cluster' gui screen I am getting the following error: Error creating cluster: OpsCenter was able to get the cluster name but not list ...
1
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0answers
208 views

Cassandra: Can't start service with error: java.lang.IllegalStateException: Unable to contact any seeds

System info: Linux stg-univ-cassandra06 2.6.32-358.23.2.el6.x86_64 #1 SMP Wed Oct 16 18:37:12 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux Cassandra version: 2.0.1 JVM vendor/version: Java HotSpot(TM) ...
1
vote
1answer
22 views

How to reuse perf charts in OpsCenter from datastax?

Key idea of my question is that I want to use my predefined list of charts from OpsCenter for different keyspaces. So I need to figure out it there any possibility to create list of performance plots ...
1
vote
0answers
49 views

Not able to view data through Hive mapping to Cassandra

After loading data from Oracle DB to Cassandra via Sqoop, I was able to view my data through both Cassandra and Hive. I was told that while doing so, 2 files would be generated for each, creating ...
1
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0answers
33 views

Changing Cassandra Tokens on 1.2.1 From 4 to 256

We initially started our cluster using one datacenter, one rack, and the Simple replication strategy. We have keyspaces with several hundred gigabytes of data. When we changed the tokens in the ...
1
vote
0answers
257 views

Use Amazon SNS to send nagios alerts

Is there any way by which I can send nagios alerts to Amazon SNS ? I have tried with following steps, but its giving me this error in the Nagios log file: Jul 12 11:38:23 ip-10-134-13-204 nagios3: ...
1
vote
1answer
56 views

Diskless Cassandra nodes?

Would it be at all feasible to use diskless nodes for cassandra? Im imagining a setup with one 'master node' that had all the appropriate software, disks, etc and the rest would PXE boot. The setup ...
1
vote
1answer
197 views

Taking Cassandra Backups

We currently have 12 nodes running in our Cassandra cluster. Ultimately even if a couple of the nodes go down, we're still up and running. The paranoia in me would like to do at least one backup a day ...
1
vote
1answer
67 views

Uneven cassandra load

I have a 10 node ring & all the nodes seem to share about the same amount of data except one is considerably less does anyone have ideas? Rack Status State Load Owns ...
1
vote
1answer
115 views

How to find date/time used by Cassandra

Earlier this morning I noticed that one of the nodes in our Cassandra cluster is writing logs an hour in the future, despite the date/time being correct on the OS. A couple of other nodes I checked ...
1
vote
2answers
229 views

How to build snappy-java under FreeBSD 8.1? (build error)

I'm trying to build snappy-java for FreeBSD 8.1 to use it with cassandra (can't enable columns compression without it). Trying to build it from source and getting an error: $ hg clone ...
1
vote
0answers
174 views

Cassandra, very long row (over 800.000 columns), row cache and manual repair

I seemed to have hit quite interesting problem recently while investigating my previous problem -- One ColumnFamily places data on only 3 out of 4 nodes We had a very long row with over 800.000 ...
1
vote
0answers
623 views

Cannot to connect to a Cassandra DB from localhost

I don't know if I'm on the right site, I installed OpenSolaris a single cassandra node, I don't have other node. On the same server, I install Ruby 1.8 with the gem Cassandra. If I try to connect ...
1
vote
1answer
349 views

Does anyone have any advice on administering a large Cassandra cluster? [closed]

Does anyone have any advice on administering a large Cassandra cluster (> 50 nodes)? I am looking at both Riak and Cassandra and need to know the performance and operational characteristics and ...
0
votes
1answer
141 views

What does Opscenter's 'Write Requests' count shown as ops/sec exactly mean?

I have started understanding and working with cassandra recently. I have created two Column Families. For CF1, a write is an insert into a unique row with all column values. Eg: Sequence of insert ...
0
votes
3answers
506 views

DataStax Opscenter Agent can't connect: “Unable to locate cassandra.yaml configuration file”

I have installed Datastax Community Edition v2.0.3 on a Windows Server 2012 R2 Datacenter machine. After a vanilla install, I can't connect to the database with OpsCenter because the agent failed to ...
0
votes
2answers
146 views

Opening ports in EC2

I have an ec2 instance. I have opened a port in the security group for cassandra (9160) and have cassandra listening on it. If I use nmap on the instance, that port does not show up, and I cannot ...
0
votes
1answer
161 views

0 connected nodes in datastax opscenter

Installed opscenterd on the separate node outside of the cluster, but within firewall ( aws security group ). Tested all possible ports between agents and opcenter server. No errors in the log.. ...