sparse file with cp

tar가 되면 cp도 되지 않으려나?

[링크 : https://wiki.archlinux.org/index.php/sparse_file#Copying_with_%60cp']

[링크 : https://unix.stackexchange.com/questions/390109/are-there-any-disadvantages-of-cp-sparse-always]

--sparse=WHEN               control creation of sparse files. See below         By default, sparse SOURCE files are detected by a crude heuristic and the corresponding DEST file is made sparse as well.  That is the behavior selected by --sparse=auto.  Specify --sparse=always to create a sparse DEST file whenever the SOURCE file contains a long enough sequence of zero bytes.  Use --sparse=never to inhibit creation of sparse files.

--sparse=auto 기본값

--sparse=always SOURCE에 0x00으로 쓰여진 충분히 긴 데이터를 포함하더라도 DEST 를 항상 sparse 파일로 생성

--sparse=never sparse 파일 생성을 금지

[링크 : http://man7.org/linux/man-pages/man1/cp.1.html]

+

DBMS에서도 이런류의 파일을 만든다고.. 

-S, --sparse               Handle sparse files efficiently.  Some files in the file system may have segments which were actually never written (quite often these are database files created by such systems as DBM).  When given this option, tar attempts to determine if the file is sparse prior to archiving it, and if so, to reduce the resulting archive size by not dumping empty parts of the file.

[링크 : http://man7.org/linux/man-pages/man1/tar.1.html]