Ah, there is a cognitive disconnect... more below. Philip Brown wrote: >> relling wrote: >> This question makes no sense to me. Perhaps you can >> rephrase? >> >> > > To take a really obnoxious case: > lets say I have a 1 gigabyte filesystem. It has 1.5 gigabytes of physical > disk allocated to it (so it is 66% full). > It has 10x100meg files in it. > > "Something bad happens", and I need to do a restore. > The most recent zsend data, has all 10 files in it. 9 of them have not been > touched since the zsend was done. > > Now, since zfs has data integrity checks, yadda yadda yadda, it should be > able to determine relatively easily, "The file on the zfs send, is the exact > same file on disk". > So, when I do a zfs receive, it would be "really nice", if there were some > way for zfs to figure out, lets say, "recieve to a snapshot of the > filesystem; then take advantage of the fact that it is a snapshot, to NOT > write on disk, the 9 unaltered files that are in the snapshot; just allocate > for the altered one". > > it would be really nice for zfs to have the smarts to do this, WITHOUT having > to potentially throw a laaarge amount of extra hard disk space for snapshots. > I want the "snapshot" space to be allocated on TAPE, not hard disk, if you > see what I mean. > If one 100meg file gets replace every 2 days, I wouldnt want to use snapshots > on the filesystem, if there was a disk space limitation. >
The cognitive disconnect is that snapshots are blocks, not files. Therefore, the snapshot may contain only changed portions of files and blocks from a single file may be spread across many different snapshots. Perhaps you are really looking for a more traditional, file-oriented backup capability. > (I know there are solutions such as samfs for this, but. I'm looking for a > zfs solution, if possible, please?) > ADM is the samfs equivalent for ZFS. http://opensolaris.org/os/project/adm/ -- richard > and help with the other parts of my original email, would still be > appreciated :) > _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
