Checksums

WiredTiger optionally checksums file reads and writes to detect storage failures. In read-only applications, or when file compression provides any necessary checksum functionality, or when using backing storage systems where blocks require no validation, performance can be increased by turning off checksum support when calling the WT_SESSION::create method.

Checksums can be configured to be "off" or "on", as well as "uncompressed". The "uncompressed" configuration checksums blocks not otherwise protected by compression. For example, in a system where the compression algorithms provide sufficient protection against corruption, and when writing a block which is too small to be usefully compressed, setting the checksum configuration value to "uncompressed" causes WiredTiger to checksum the blocks which are not compressed:

    error_check(session->create(
      session, "table:mytable", "key_format=S,value_format=S,checksum=uncompressed"));

The default WiredTiger configuration is uncompressed.