Julian Regel <jrmailgate-zfsdisc...@yahoo.co.uk> wrote:
> When I look at the documentation for Zmanda
> (http://docs.zmanda.com/Project:Amanda_Enterprise_3.0/ZMC_Users_Manual/Appendix_A:_Backing_Up_and_Restoring_Solaris_ZFS),
> it states that the command used to backup a ZFS filesystem depends on
> whether backing up ACLs are required (the default is not to(!)). If backing
> up ACLs are required - which they are for us - then the native /usr/bin/tar
> command is used. Given that /usr/bin/tar doesn't handle sparse files
> correctly and updates atime when creating archives, it's not possible to
> create a complete copy of a filesystem without making intrusive changes to
> the structure of the data and/or metadata.
>
> So it's arguable that ufsdump was a significant improvement over tar, and
> that the current archiving solutions for ZFS are actually a step backwards.
>
> > From my perspective, Sun really need to create a zfsdump/zfsrestore set of
> > commands that perform block level backups of a specified filesystem (or
> > snapshot) and that preserves ACLs, atime, sparse files, handles multiple
> > tapes (many of us still use and rely on tape!) etc.
Sun's tar is not able to archive files > 8 GB in a way that can be read on any
other OS unless you use star. This is because Sun's tar does not implement
support for the POSIX.1-2001 extended tar format.
Sun's tar also writes ACLs in a way that is 100% non-portable. Star cannot
understand them and probably never will be able to understand this format as it
is not well defined for a portable program like star.
Star supports to do backups without affecting atime (on Solaris) since 15 years
already and star supports the withdrawn POSIX draft ACLs in a OS independent
way. This allows to use star for platform independent ACL support in case you
are using UFS on Solaris.
Star will in future support NTFS ACLs in a OS independent way. If someone likes
to contribute, he is of course welcome. As I am currently working on
cdrtools-3.0-final, star is currently on maintenance only.
What we need for the future is a OS/FS independent program that implements the
needed features.
Jörg
--
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joerg.schill...@fokus.fraunhofer.de (work) Blog:
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