Apache Cassandra is an open source distributed database management system.

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7
votes
2answers
579 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 ...
7
votes
1answer
921 views

How to resolve a stuck major compaction in Apache Cassandra?

I've got a one-node Cassandra cluster which is currently stuck in a major compaction process. After executing a nodetool compactit started the compaction and I see the tmp-sstable files with a size of ...
5
votes
3answers
657 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
2k 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
768 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
872 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: ...
3
votes
3answers
766 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 ...
3
votes
1answer
429 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 ...
3
votes
1answer
2k 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 ...
3
votes
2answers
487 views

Tunneling cassandra via ssh gives me a connection closed error

I have a server with two network interfaces. Cassandra is listening on a dedicated internal database network on eth1 (not accessable from outside). So I do my tunnel like this: ssh -f -N ...
3
votes
1answer
2k 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
1answer
220 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 ...
2
votes
2answers
4k 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
935 views

Cassandra: do more storage size, needs more CPU and RAM

I have gone through the recommended architecture of the Cassandra node configuration! according to which the recommended hardware infrastructure for the node is to have RAM: 16-32 GB, storage: 500GB ...
2
votes
1answer
96 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
2answers
477 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 ...
2
votes
1answer
4k 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 ...
2
votes
1answer
140 views

Incredibly high load average on a Centos server

I have a Centos 6.4 server that's being used as a Cassandra node in a production environment, it is still working and responding to queries etc, but the load average is rather "high" a.k.a. buggy? In ...
2
votes
1answer
252 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
84 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
379 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
154 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
0answers
164 views

Does nodetool repair repair the next node?

Let's assume we have a Cassandra cluster with the following ring: A -> B -> C -> D (no virtual nodes), and we assume that all the data is stored at RF=2. Now let's say that B dies, leaving us ...
2
votes
1answer
296 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
87 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 ...
2
votes
1answer
756 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
2answers
984 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
200 views

Cassandra: understanding replication factor

Hypothetical situation: Setup a cassandra cluster with N nodes. Create a keyspace and set replication_factor to 1 and use SimpleStrategy. Add some data. Remove 1 node. Does this mean that 1/N of ...
1
vote
3answers
2k 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
191 views

Operator \> and \< (string version comparison) are not recognised in shell script

I am trying to run Casandra nodetool and getting warnings coming from .sh script. [root@d11ca4cc-fa95-c8a9-e133-e64c434f0e6f ~]# nodetool status /opt/local/share/cassandra/bin/nodetool[53]: .[97]: ...
1
vote
2answers
279 views

Uneven Cassandra load

Should a three node Cassandra cluster with a replication factor of 3 have the same load value for all three nodes? We are using a random partitioner and NetworkTopologyStrategy. Nodetool ring shows ...
1
vote
1answer
255 views

cassandra nodetool repair - how to schedule properly?

Im putting together a 16 node cassandra cluster (replication factor 2) and want to setup a schedule for nodetool repair. gc_grace_seconds is at the default. Two questions: My first impulse is to ...
1
vote
2answers
192 views

How to authenticate with cassandra-stress 2.1

Is there a way to authenticate to cassandra using the new cassandra-stress tool released with cassandra 2.1? It appears as if the '-un' (username) and '-pw' (password) switches have been removed from ...
1
vote
2answers
79 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
852 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
131 views

4 node cassandra - skip redundancy?

After much pleading and case building my group got the budget to buy 4 nodes and start a cassandra cluster. Each machine has 3x1Tb drives so I'm wondering whether it's reasonable to skip the 1 way ...
1
vote
1answer
37 views

cassandra setup - uneven load - what did I do wrong?

For the sake of understanding I setup a 4 node cluster using the latest/greatest(released) version of Cassandra. The four nodes were brought up in sequence using almost entirely default settings and ...
1
vote
1answer
1k views

Setting-up OpsCenter gives: scp /tmp/.. Permission denied

I'm trying to setup OpsCenter by adding my localhost Cassandra node (for testing). The login credentials I used for SSH has sudo/root rights, nevertheless I get the error: scp: /tmp/tmpXInRfq: ...
1
vote
2answers
169 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
731 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
706 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
534 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
299 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
413 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
807 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
623 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
17 views

Trouble configuring Opscenter (5.1.1) Email alerts

I was wondering if anyone could assist me in figuring out why my opscenter email alerts aren't working. My environment is docker running in native network mode with opscenter in a container. ...
1
vote
1answer
197 views

nodetool repair fails with snapshot error

When running nodetool repair, the repair fails on the system_auth keyspace with the following log entries: INFO [AntiEntropySessions:5] 2015-03-17 20:00:34,795 RepairSession.java:260 - [repair ...
1
vote
3answers
1k views

DataStax OpsCenter agent fails to start when Cassandra requires authentication

Problem I can not get OpsCenter get to connect to datastax-agent. It seems that datastax-agent starts and tries to connect to cassandra, fails because it does not know the correct credentials, but it ...
1
vote
0answers
253 views

Repairing OpsCenter rollups60 Results in Snapshot Errors

I am running a 6 node cluster using Apache Cassandra 2.1.2 with DataStax OpsCenter 5.0.2 from the AWS EC2 AMI "DataStax Auto-Clustering AMI 2.5.1-hvm" (DataStax Community AMI). When I try to run a ...