We have 8 node cluster. Replication factor is 3. For some of the nodes the Disk usage (du -ksh .) in the data directory for CF doesn't match the Load reported in nodetool ring command. When we expanded the cluster from 4 node to 8 nodes (4 weeks back), everything was okay. Over period of last 2-3 weeks the disk usage has gone up. We increased the RF from 2 to 3 2 weeks ago.
I am not sure if increasing the RF is causing this issue. For one of the nodes that I analyzed: 1. nodetool ring reported load as 575.38 GB 2. nodetool cfstats for the CF reported: SSTable count: 28 Space used (live): 572671381955 Space used (total): 572671381955 3. 'ls -1 *Data* | wc -l' in the data folder for CF returned 46 4. 'du -ksh .' in the data folder for CF returned 720G The above numbers indicate that there are some sstables that are obsolete and are still occupying space on disk. What could be wrong? Will restarting the node help? The cassandra process is running for last 45 days with no downtime. However, because the disk usage is high, we are not able to run full compaction. Also, I can't find reference to each of the sstables on disk in the system.log file. For eg I have one data file on disk as (ls -lth): 86G Nov 20 06:14 I have system.log file with first line: INFO [main] 2013-11-18 09:41:56,120 AbstractCassandraDaemon.java (line 101) Logging initialized The 86G file must be a result of some compaction. I see no reference of data file in system.log file between 11/18 to 11/25. What could be the reason for that? The only reference is dated 11/29 when the file was being streamed to another node (new node). How can I identify the obsolete files and remove them? I am thinking about following. Let me know if it make sense. 1. Restart the node and check the state. 2. Move the oldest data files to another location (to another mount point) 3. Restart the node again 4. Run repair on the node so that it can get the missing data from its peers. I compared the numbers of a healthy node for the same CF: 1. nodetool ring reported load as 662.95 GB 2. nodetool cfstats for the CF reported: SSTable count: 16 Space used (live): 670524321067 Space used (total): 670524321067 3. 'ls -1 *Data* | wc -l' in the data folder for CF returned 16 4. 'du -ksh .' in the data folder for CF returned 625G -Naren -- Narendra Sharma Software Engineer *http://www.aeris.com <http://www.aeris.com>* *http://narendrasharma.blogspot.com/ <http://narendrasharma.blogspot.com/>*
