Question:
When restoring from snapshot, is there a method which will not recreate data in the real data area.
Example:
Random files are removed throughout the filer. We decide to backtrack to Mondays snapshot. We plan to copy everything out of snapshot back to the real data area.
Solution 1: use 'find' and 'cpio' and transfer all the data back. this would appear to require 2x current capacity of the filer to replicate all data out of snapshot. if you're using >50%, this method would fail.
Solution 2: use 'find' and 'diff' and 'cpio' to enhance solution 1 with a check. Now only files which differ from the snapshot will be replaced.
Solution 3: dump the snapshot to tape, and then restore from tape after removing existing snapshots.
Solution 4: boot from floppy, use prev_cp and wack? Has anyone had any experience with 'prev_cp' and 'wack'? We're leaning at #4. Any comments would greatly be appreciated!
######################################## # Christoph Doerbeck # Motorola ISG # email: doerbeck@dma.isg.mot.com
In message 199804221400.KAA21557@prospero.dma.isg.mot.com, Christoph Doerbeck writes:
Solution 1: use 'find' and 'cpio' and transfer all the data back. this would appear to require 2x current capacity of the filer to replicate all data out of snapshot. if you're using >50%, this method would fail.
If the files in question have been removed, rather than modified, this will only copy the files that have been removed. On other files, it will either refuse to copy because it thinks its copying a file onto itself. It will complain the whole while (slowing things down), but it will only add the space consumed by the deleted files. At least that's what happened when I tried it in my home directory.
--bob--
In message 199804221400.KAA21557@prospero.dma.isg.mot.com, Christoph Doerbeck writes:
Solution 3: dump the snapshot to tape, and then restore from tape after removing existing snapshots.
Solution 4: boot from floppy, use prev_cp and wack? Has anyone had any experience with 'prev_cp' and 'wack'?
These two solutions exercise code which, while tested, is not as well tested or exercised as the normal case. We test it in house, but since we don't have an active customer base running wack or restore on a daily basis, they aren't as reliable as access through the file system, they aren't as reliable. They have the additional disadvantage that they start by destroying data, so if they don't work, you're stuck.
--bob--
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Christoph Doerbeck -
Robert English