Apache Cassandra is an open source distributed database management system.

learn more… | top users | synonyms

9
votes
1answer
2k 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 ...
7
votes
2answers
692 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 ...
5
votes
3answers
927 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?
4
votes
1answer
241 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 ...
3
votes
6answers
895 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
1k 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: ttp://www.datastax.com/documentation/...
3
votes
3answers
1k 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
3k 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 -...
3
votes
2answers
2k 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 -L9161:192....
3
votes
1answer
540 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
3k 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
688 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 ...
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
2answers
482 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 ...
2
votes
2answers
5k 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
352 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
4k views

datastax-agent Cannot connect Error

Seeing an issue with the Opscenter Agents. Opscenter reports the agents are not connected and in the agent.log on each node, they all report the following: com.datastax.driver.core.exceptions....
2
votes
1answer
131 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
286 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
424 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
99 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
427 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
194 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
440 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
110 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
869 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
1k 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: "192.168.0.101,192....
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 apt-...
1
vote
1answer
309 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
397 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
555 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
682 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
1answer
729 views

Opscenter 5.0: error when adding cluster, cluster added anyway, no clusters shown

I have a new Opscenter installation. After adding my "existing cluster" to opscenter, I get the following error dialog boxes: Error creating cluster: Cannot read property 'datasource' of undefined ...
1
vote
2answers
85 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
891 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
306 views

Mesos slave IP for Marathon-launched ( docker container ) service instance

i have a docker image i would like to launch a couple instances of via Mesos/Marathon. i'm using BRIDGE networking in docker, and i would like to pass in the "public" ( i.e. not the container's ...
1
vote
1answer
234 views

What is the best way to get a list of nodes that belong to a Cassandra cluster?

I'm creating some scripts for some Cassandra clusters I operate. Some of these scripts need a list of nodes that are part of the cluster. nodetool status will print a list of the nodes and their ...
1
vote
1answer
672 views

Opscenter can not connect to the nodes

Our opscenter can not connect to the nodes, in the logs the next error appears: 2015-08-17 08:56:37+0200 [SNPaware_Cluster] INFO: Nodes with agents that appear to be no longer running: 172.31.7.245, ...
1
vote
1answer
122 views

Cassandra 2.0.16 pending tasks reporting bug?

Yesterday I upgraded my Cassandra cluster from 2.0.14 to 2.0.16, after upgrade, I am start seeing some strange behaviours of "PendingTasks" reporting. The Cassandra repository I am using is datastax,...
1
vote
1answer
457 views

Cannot add an existing Cassandra cluster to OpsCenter ('ascii' codec can't encode character)

While trying to add an existing Cassandra cluster to OpsCenter I encountered the following error: Error creating cluster: 'ascii' codec can't encode character u'\u03a7' in position 0: ordinal not ...
1
vote
1answer
474 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
74 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
2k views

Cassandra 2.x - cluster does not rebalance after adding new nodes

I had 3 nodes, all with ~550GB, and added 4 more. I hoped that data would migrate on its own from old servers to new ones. Unfortunately after one day, data seems to stay in old places. In parallel, ...
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
1answer
329 views

Cassandra - moving data from multiple nodes to a single node

I need to copy data from 3 nodes to a single node. I know about snapshot command and I was able to successfully copy data from a cluster where each node had 100% data (full replication) to a single-...
1
vote
2answers
254 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
1k 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
962 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 ...