The xbstream binary overview¶
To support simultaneous compression and streaming, a new custom streaming format called xbstream was introduced to Percona XtraBackup in addition to the TAR format. That was required to overcome some limitations of traditional archive formats such as tar, cpio and others which did not allow streaming dynamically generated files, for example dynamically compressed files. Other advantages of xbstream over traditional streaming/archive format include ability to stream multiple files concurrently (so it is possible to use streaming in the xbstream format together with the –parallel option) and more compact data storage.
This utility has a tar-like interface:
-xoption it extracts files from the stream read from its standard input to the current directory unless specified otherwise with the
-coption. Support for parallel extraction with the
--paralleloption has been implemented in Percona XtraBackup 2.4.7.
-coption it streams files specified on the command line to its standard output.
--decrypt=ALGOoption specified xbstream will automatically decrypt encrypted files when extracting input stream. Supported values for this option are:
--encrypt-key-fileoptions must be specified to provide encryption key, but not both.
--encrypt-threadsoption you can specify the number of threads for parallel data encryption. The default value is
--encrypt-keyoption is used to specify the encryption key that will be used. It can’t be used with
--encrypt-key-fileoption because they are mutually exclusive.
--encrypt-key-fileoption is used to specify the file that contains the encryption key. It can’t be used with
--encrypt-keyoption. because they are mutually exclusive.
The utility also tries to minimize its impact on the OS page cache by using the
posix_fadvise() calls when available.
When compression is enabled with xtrabackup all data is compressed, including the transaction log file and meta data files, using the specified compression algorithm. Read more about supported compression algorithms in the Create a compressed backup document.