NAME

       xbstream - Percona xbstream Documentation

       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:

          • with  the -x option it extracts files from the stream read from its standard input to
            the current directory unless specified otherwise with  the  -c  option.  Support  for
            parallel  extraction  with  the  --parallel  option  has  been implemented in Percona
            XtraBackup 2.4.7.

          • with the -c option it streams files specified on the command  line  to  its  standard
            output.

          • with   the  --decrypt=ALGO  option  specified  xbstream  will  automatically  decrypt
            encrypted files when extracting input stream. Supported values for this  option  are:
            AES128,  AES192,  and AES256. Either --encrypt-key or --encrypt-key-file options must
            be specified  to  provide  encryption  key,  but  not  both.  This  option  has  been
            implemented in Percona XtraBackup 2.4.7.

          • with  the --encrypt-threads option you can specify the number of threads for parallel
            data encryption. The default value is 1. This option has been implemented in  Percona
            XtraBackup 2.4.7.

          • the  --encrypt-key option is used to specify the encryption key that will be used. It
            can't be used with --encrypt-key-file option because  they  are  mutually  exclusive.
            This option has been implemented in Percona XtraBackup 2.4.7.

          • the  --encrypt-key-file  option  is  used  to  specify  the  file  that  contains the
            encryption key. It can't  be  used  with  --encrypt-key  option.   because  they  are
            mutually exclusive. This option has been implemented in Percona XtraBackup 2.4.7.

       The  utility  also  tries  to  minimize  its  impact  on  the  OS  page cache by using the
       appropriate posix_fadvise() calls when available.

       When compression is enabled with xtrabackup all data is being  compressed,  including  the
       transaction  log  file and meta data files, using the specified compression algorithm. The
       only currently supported algorithm is quicklz.

       The resulting files have the qpress archive format, i.e.,  every  *.qp  file  produced  by
       xtrabackup  is essentially a one-file qpress archive and can be extracted and uncompressed
       by the qpress file archiver. This means that there is no need to decompress entire  backup
       to restore a single table as with tar.gz.

       To decompress individual files, run xbstream with the --decompress option. You may control
       the number of threads used for decompressing by passing the --decompress-threads option.

       Also, files can be decompressed using the qpress tool that can be  downloaded  from  here.
       Qpress supports multi-threaded decompression.

AUTHOR

       Percona LLC and/or its affiliates

COPYRIGHT

       2009-2022, Percona LLC and/or its affiliates