如何清理Cassandra数据库？

Question

> Blockquote
users-6521507045b511e9b987d3bcf2375bd1
users-86d8a89045af11e9b987d3bcf2375bd1
users-e3548ac045b011e9b987d3bcf2375bd1

cassandra创建多个目录，如何删除未使用的目录？

Answer 1

Cassandra在删除或截断表/键空间时会保留删除的数据作为安全保护。

如果您查看这些目录，则会发现除了快照之外它们是空的：

.
./backups
./snapshots
./snapshots/dropped-1546614808079-compacted
./snapshots/dropped-1546614808079-compacted/mc-1-big-Digest.crc32
./snapshots/dropped-1546614808079-compacted/mc-1-big-Statistics.db
./snapshots/dropped-1546614808079-compacted/mc-1-big-Data.db
./snapshots/dropped-1546614808079-compacted/mc-1-big-Filter.db
./snapshots/dropped-1546614808079-compacted/mc-1-big-CompressionInfo.db
./snapshots/dropped-1546614808079-compacted/mc-1-big-TOC.txt
./snapshots/dropped-1546614808079-compacted/mc-1-big-Index.db
./snapshots/dropped-1546614808079-compacted/mc-1-big-Summary.db

nodetool clearsnapshot将删除这些快照。之后，我使用简单的find /var/lib/cassandra/data**/ -type d -empty -print进行清理。但是要小心，当生成新表和键空间时，这也会删除它们的文件夹-我不知道Cassandra是如何处理的。