Oracle 23c New Features for DBA'sAs like in ASM, when ever a disk is added a rebalance operation takes place between the disks, similarly when the replication factor is changed at keyspace level in the cassandra, the rebalance operation should take place, I have changed the replication factor for Keyspace and you should start the repair of each node so […]
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Undo like pointers, tombstones Cassandra uses a log-structured storage engine. Because of this, deletes do not remove the rows and columns immediately and in-place. Instead, Cassandra writes a special marker, called a tombstone, indicating that a row, column, or range of columns was deleted. These tombstones are kept for at least the period of time […] Partition Merging or Compact or merging ss tables Cassandra does not do in-place writes or updates. Rather, it uses a log structured format. Writes are done to Memtables, which are periodically flushed to disk as SSTables. As a result of this approach, the number of SSTables grows over time. Having multiple SSTables causes […] Shutdown Best Practice While Cassandra is crash-safe, you can make a cleanershutdown and save some time during startup thus: – Make other nodes think this one is down. – nodetool -h $(hostname) -p 8080 disablegossip – Wait a few secs, cut off anyone from writing to this node. – nodetool -h $(hostname) -p […] As like oracle 100046 , you can also trace the Cassandra Session and it provide you the following information , the highlighted blue parts are important to understand that data has been fetched from different nodes and how many undo it has to read and how many from cache and how many reads […] Backup in Cassandra maintain at node level , so any backup that taken in the one node does not contain other nodes data, so you must take backup of each node, cassandra maintains backups as snapshots means an entire sstables at disk level copied to a different folder with snapshot id as like below. root@wash-i-16ca26c8-prod […] ############# Memory Calculation for Cassandra (kind of sga setting 🙂 will be done during environment setup with following script excerpt. if you want you can change accordingly this script and restart the cassandra. ################## geek_cluster/node1/resources/cassandra/conf/cassandra-env.sh …. half_system_memory_in_mb=`expr $system_memory_in_mb / 2` quarter_system_memory_in_mb=`expr $half_system_memory_in_mb / 2` if [ “$half_system_memory_in_mb” -gt “1024” ] then […] We also set timeouts for client side, TNSNAMES.ora or sqlnet.ora (Client Side) root@wash-i-16ca26c8-prod ~/.ccm/repository/4.5.2/resources/cassandra/conf $ vi cqlshrc.default root@wash-i-16ca26c8-prod ~/.ccm/repository/4.5.2/resources/cassandra/conf $ Set the client_timeout as like sqlnet.ora timeout setting [connection] hostname = 192.168.1.2 port = 9160 client_timeout=40 ################################### Node Communication Settings * Timeouts ################################### root@wash-i-16ca26c8-prod ~/.ccm/geek_cluster/node1/resources/cassandra/conf $ root@wash-i-16ca26c8-prod ~/.ccm/geek_cluster/node1/resources/cassandra/conf […] Alert Log and tracing Parameters in Cassandra.yaml log4j-server.properties log4j.appender.R.File=/root/.ccm/geek_cluster/node1/logs/system.log root@wash-i-16ca26c8-prod ~ $ ccm node1 nodetool getlogginglevels Logger Name Log Level root INFO org.apache.solr.core.SolrCore WARN org.apache.thrift.server.TNonblockingServer FATAL org.apache.solr.handler.component WARN org.apache.solr.search.SolrIndexSearcher WARN org.apache.solr.update WARN org.apache.solr.core.CassandraSolrConfig WARN SolrValidationLog INFO org.apache.solr.core.RequestHandlers WARN org.apache.solr.util.plugin.AbstractPluginLoader WARN root@wash-i-16ca26c8-prod ~ $ root@wash-i-16ca26c8-prod ~/.ccm/geek_cluster/node1/logs $ ls -ltr total 528 […] Archive Logs & Redologs (commit logs) Parameters that need to effect. commitlog_directory: /root/.ccm/geek_cluster/node1/commitlogs commitlog_directory: /root/.ccm/geek_cluster/node1/commitlogs commitlog_segment_size_in_mb: 32 commitlog_sync: periodic commitlog_sync_period_in_ms: 10000 /.ccm/geek_cluster/node1/resources/cassandra/conf/commitlog_archiving.properties file to keep archive_command Argument 1 will give you the path to the files you’d want to copy, while
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