sstablesplit
Big sstable files can take up a lot of disk space. The sstablesplit tool can be used to split those large files into smaller files. It can be thought of as a type of anticompaction.
Cassandra must be stopped before this tool is executed, or unexpected results will occur. Note: the script does not verify that Cassandra is stopped.
Usage
sstablesplit <options> <filename>
| --debug | display stack traces |
|---|---|
-h, --help |
display this help message |
--no-snapshot |
don’t snapshot the sstables before splitting |
-s, --size <size> |
maximum size in MB for the output sstables (default: 50) |
This command should be run with Cassandra stopped. Note: the script does not verify that Cassandra is stopped.
Split a File
Split a large sstable into smaller sstables. By default, unless the option --no-snapshot is added, a snapshot will be done of the original sstable and placed in the snapshots folder.
Example:
sstablesplit /var/lib/cassandra/data/keyspace/eventlog-6365332094dd11e88f324f9c503e4753/mc-8-big-Data.db Pre-split sstables snapshotted into snapshot pre-split-1533144514795
Split Multiple Files
Wildcards can be used in the filename portion of the command to split multiple files.
Example:
sstablesplit --size 1 /var/lib/cassandra/data/keyspace/eventlog-6365332094dd11e88f324f9c503e4753/mc-1*
Attempt to Split a Small File
If the file is already smaller than the split size provided, the sstable will not be split.
Example:
sstablesplit /var/lib/cassandra/data/keyspace/eventlog-6365332094dd11e88f324f9c503e4753/mc-8-big-Data.db Skipping /var/lib/cassandra/data/keyspace/eventlog-6365332094dd11e88f324f9c503e4753/mc-8-big-Data.db: it's size (1.442 MB) is less than the split size (50 MB) No sstables needed splitting.
Split a File into Specified Size
The default size used for splitting is 50MB. Specify another size with the --size option. The size is in megabytes (MB). Specify only the number, not the units. For example --size 50 is correct, but --size 50MB is not.
Example:
sstablesplit --size 1 /var/lib/cassandra/data/keyspace/eventlog-6365332094dd11e88f324f9c503e4753/mc-9-big-Data.db Pre-split sstables snapshotted into snapshot pre-split-1533144996008
Split Without Snapshot
By default, sstablesplit will create a snapshot before splitting. If a snapshot is not needed, use the --no-snapshot option to skip it.
Example:
sstablesplit --size 1 --no-snapshot /var/lib/cassandra/data/keyspace/eventlog-6365332094dd11e88f324f9c503e4753/mc-11-big-Data.db
Note: There is no output, but you can see the results in your file system.
