[LUDOC-514] tar --acls option for proper POSIX ACLs backup/restore of MDTs

• Type: Improvement
• Resolution: Fixed
• Priority: Major
• Severity: 3
• Assignee: Lustre Manual Triage
• Reporter: Stephane Thiell

Description

Tar does only restore the following xattr if --acls is provided:

system.posix_acl_access
system.posix_acl_default

See: https://git.savannah.gnu.org/cgit/tar.git/tree/src/xattrs.c#n283

The documentation should be updated to mention --acls for MDT backup/restore, otherwise all POSIX ACLs are lost. I will submit a doc patch shortly.

Alternatively, one can use getfacl/setfacl to backup/restore ACLs.

Lastly, using -P / --absolute-names speeds up tremendously the extraction for trusted archive with hardlinks (like MDT backup archives).
See:

• https://mort.coffee/home/tar/
• https://www.gnu.org/software/tar/manual/html_node/absolute.html