ZFS: backup, snapshot, rollback, restore, boot and more
Posted by Graham Perrin on 28 May 2007
Rollback/restore
I’m aware of ZFS rollback of an entire system … but I vaguely recall reading somewhere that ZFS commands can also be more discrete - rollback or restore of directories or individual files.
John Clingan describes rollback of zones on a ZFS system but zones in this context are limited to Solaris; I’m more interested in ZFS on Mac. Also, zoning does not match the level of discretion (individual files) that I’m seeking.
Am I mistaken in my recollection of
ZFS commands for directory-level or
file-level rollback?
A March 2007 dicussion File level snapshots in ZFS? suggests CVS or other version control methods. My own thoughts are in line with those of Manoj Joseph within that discussion, but I can’t find a reply to his comments.
Advice/clarification will gratefully appreciated.
My current foci are ZFS for MacFusion and for Linux — keywords for both: FUSE. I’m aware of ZFS for FUSE on Linux and I’m extremely keen on the idea of ZFS for the MacFusion Project with which I’m involved.A May 2006 article ZFS on YOUR Desktop (as noted there, Apple Time Machine is reminiscent) presents an appealing picture.Until recently I have often referred to ZFS: the last word in file systems (2005) but I now find more recent information presenting things in greater clarity:
- St. Petersburg at OpenSolaris.org | How ZFS Works (11 April 2007)
- ZFS FAQ at OpenSolaris.org
- ZFS Source Tour at OpenSolaris.org.
ZFS boot support
Backup, snapshot, rollback and restore aside:
it’s great to read about boot support!
28 May 2007 at 14:20
ZFS supports filesystem rollback. What Richard Relling meant in his response on the opensolaris thread was that you can use a ZFS filesystem as the filesystem for a CVS or SVN repository, and can use the source code control features to rollback files.
As ZFS snapshots cover the entire filesystem, you can rollback to a given point in time, but not a given file. If you snapshot, for example, once every hour, you can roll the filesystem back to what it looked like N hours ago. New files created since then will be gone, but the file you were looking for will be there. Note that you can use the .zfs/snapshot directory to look for individual files and cp them to recover them. But again, this is only possible if you’ve got a snapshot to refer to.
28 May 2007 at 16:49
Graham Perrin:
— thanks Mark J Musante for the focus; what he mentions is familiar
— recalls that Solaris 10 bootable install media was/is not bootable in Parallels Desktop for Mac
— wonders where he bookmarked the workaround for that incompatibility
— prepares to boot Ubuntu 7.04 in a VM to maybe dabble with ZFS in FUSE on Linux.
… so, the snapshot directory is browsable/searchable at the command line without actually rolling back the system?