Migrating to incremental repairs
To start using incremental repairs, migrate the SSTables on each node. Incremental repair skips SSTables that are already marked as repaired. These steps ensure the data integrity when changing the repair strategy from full to incremental.
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DataStax recommends using full repairs. Incremental repairs may cause performance issues, see CASSANDRA-9143. |
Prerequisites
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Before starting this procedure, be aware that the first system-wide full repair (3) can take a long time, as the database recompacts all SSTables. To make this process less disruptive, migrate the cluster to incremental repair one node at a time. |
Procedure
In a terminal:
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Disable autocompaction on the node:
nodetool disableautocompactionTarball path:`<install_directory>/bin`
Running nodetool disableautocompaction without parameters disables autocompaction for all keyspaces.
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Before running a full repair (3), list the nodes SSTables located in
/var/lib/cassandra/data. You will need this list to run the command to set therepairedAtflag in 5.The
datadirectory contains a subdirectory for each keyspace. Each subdirectory contains a set of files for each SSTable. The name of the file that contains the SSTable data has the following format:<version_code>-<generation>-<format>-Data.db -
Run the default full, sequential repair on one node at a time:
nodetool repairTarball path:
<install_directory>/binRunning nodetool repair without parameters runs a full sequential repair of all SSTables on the node and can take a substantial amount of time.
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Using the list you created in 2, set the
repairedAtflag on each SSTable using sstablerepairedset to--is-repaired.Unless you set the
repairedAtto repaired for each SSTable, the existing SSTables might not be changed by the repair process and any incremental repair process that runs later will not process these SSTables.-
To mark a single SSTable:
sudo sstablerepairedset --really-set --is-repaired <SSTable-example-Data.db> -
For batch processing, use a text file of SSTable names:
sudo sstablerepairedset --really-set --is-repaired -f <SSTable-names.txt>
Tarball path:`<installation_location>/resources/cassandra/tools/bin`
The value of the repairedAt flag is the timestamp of the last repair. The sstablerepairedset command applies the current date/time. To check the value of the
repairedAtflag, use:sstablemetadata <example-keyspace>-<SSTable-example-Data.db> | grep "Repaired at" -
What’s next
After you have migrated all nodes, you can run incremental repairs using nodetool repair with the -inc option.
Related information
