Dear Wiki user, You have subscribed to a wiki page or wiki category on "Cassandra Wiki" for change notification.
The "Operations" page has been changed by EricEvans. The comment on this change is: some words about json export/import. http://wiki.apache.org/cassandra/Operations?action=diff&rev1=16&rev2=17 -------------------------------------------------- To revert to a snapshot, shut down the node, clear out the old commitlog and sstables, and move the sstables from the snapshot location to the live data directory. === Import / export === - Cassandra can also export data as JSON with `bin/sstable2json`, and import it with `bin/json2sstable`. Eric to document. :) + As an alternative to taking snapshots it's possible to export SSTables to JSON format using the `bin/sstable2json` command: + + {{{ + Usage: sstable2json [-f outfile] <sstable> [-k key [-k key [...]]] + }}} + + `bin/sstable2json` accepts as a required argument, the full path to an SSTable data file, (files ending in -Data.db), and an optional argument for an output file (by default, output is written to stdout). You can also pass the names of specific keys using the `-k` argument to limit what is exported. + + Note: If you are not running the exporter on in-place SSTables, there are a couple of things to keep in mind. + 1. The corresponding configuration must be present (same as it would be to run a node). + 2. SSTables are expected to be in a directory named for the keyspace (same as they would be on a production node). + + JSON exported SSTables can be "imported" to create new SSTables using `bin/json2sstable`: + + {{{ + Usage: json2sstable -K keyspace -c column_family <json> <sstable> + }}} + + `bin/json2sstable` takes arguments for keyspace and column family names, and full paths for the JSON input file and the destination SSTable file name. == Monitoring == Cassandra exposes internal metrics as JMX data. This is a common standard in the JVM world; OpenNMS, Nagios, and Munin at least offer some level of JMX support.
