Properties

Parent property with multiple possible children.

Simple string literal.

Special case for directories: Prefix ~ can be used for user home, e.g. ~/my-app/storage

Signed integer, same as Java’s int.

Signed long, same as Java’s long.

Signed double, same as Java’s double.

true or false

Time interval, either in ISO format PnDTnHnMn.nS, or simple amount and unit amount[ns|ms|s|m|h|d], e.g. 30 M

More details in DurationParser.

Amount of bytes: amount[b|kb|kib|mb|mib|gb|big|tb|tib|pb|pib], e.g. 1.5 GB

More details in ByteSizeParser and ByteUnit.

Number of threads used by the storage engine. It depicts the numbers of subdirectories as well. Each thread manages one directory in which it writes to and reads from exclusively. The unity of thread, directory and the cached data therefore is called a "Channel".

For further information see Using Channels.

Time for the house keeping interval. House keeping tasks are, among others:

In combination with housekeeping-time-budget, it can be specified how many CPU time should be used for house keeping. E.g. interval=1000ms and budget=10000000ns means every second there’s 0.01 seconds time for house keeping, so max 1% CPU time used for house keeping. This CPU time window is only used if house keeping work is pending. If nothing has to be done, no time is wasted.

Time used for each housekeeping cycle. However, no matter how low the number is, one item of work will always be completed. But if there is nothing to clean up, no processor time will be wasted. Default is 10000000 (10 million nanoseconds = 10 milliseconds = 0.01 seconds). However, no matter how small the time is, one item is done at least. This is to avoid no-ops, if a too small time window is configured. This time budget is a "best effort" threshold, meaning when at 1ns left, a huge file has to be cleaned or the references of a huge collection have to be marked for GC, then this budget can be exceeded considerably.

For further information see Housekeeping.

Minimum file size in bytes of a storage file to avoid merging with other files during housekeeping. Must be greater than 1, maximum is 2GB.

Maximum file size in bytes of a storage file to avoid splitting in more files during housekeeping. Must be greater than 1, maximum is 2GB.

The ratio (value in ]0.0;1.0]) of non-gap data contained in a storage file to prevent the file from being dissolved. "Gap" data is anything that is not the latest version of an entity’s data, including older versions of an entity and "comment" bytes (a sequence of bytes beginning with its length as a negative value length header). The closer this value is to 1.0 (100%), the less disk space is occupied by storage files, but the more file dissolving (data transfers to new files) is required and vice versa.

Maximum file size for each channels transactions log file. If this limit is exceeded the file wile be cleaned up during housekeeping.

To shrink the file size all store, transfer, and truncation entries are combined into one single store entry for each storage files. FileCreation entries are kept, FileDeletion entries are kept if the storage data file still exists on the file system. Otherwise all entries related to deleted files are removed if the storage data file does no more exist.

Default is 100 MB. Maximum value is 1 GB.