On Mar 21, 2010, at 6:40 AM, Edward Ned Harvey wrote: >>> The only tool I'm aware of today that provides a copy of the data, >> and all of the ZPL metadata and all the ZFS dataset properties is 'zfs >> send'. >> >> AFAIK, this is correct. >> Further, the only type of tool that can backup a pool is a tool like >> dd. > > How is it different to backup a pool, versus to backup all the zfs > filesystems in a pool? Obviously, dd is not viable for most situations as a > backup tool... Is there any reason anyone would ever do it for ZFS, aside > from forensics? > > Oh, I know one difference. "dd" to backup the pool would also preserve all > the zfs snaps. But if you want, you could have done that with "zfs send" > too. > > So my question still stands: What can you backup in a zpool, using dd, that > you can't backup via "zfs send?" > > (As pointless as this may be, it's academic.) ;-)
The pool configuration, metadata (eg. DDT), and all of the datasets. Today, there are three dataset types readily available: file system, zvol, and pnfs. On the radar is a lustre dataset type. Each of the dataset types has a method of backup, even if only dd-like. The way I see it, ZFS defies traditional notions of "file system" backup because ZFS is much more than just a "file system." Not surprisingly, it looks a lot more like an Oracle database than a UFS file system, and the methods of backup for databases are similar to that provided by ZFS. -- richard ZFS storage and performance consulting at http://www.RichardElling.com ZFS training on deduplication, NexentaStor, and NAS performance Las Vegas, April 29-30, 2010 http://nexenta-vegas.eventbrite.com _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
