2009-10-23 04:11 AM
Consider a QSM between two SnapLock Compliance qtrees (resync allowed)
SLC -> SM -> SLC
If the source is destroyed (DR), you can on the primary site :
- restore from an NDMP backup
- restore from a disk copy (SM or vol copy) made from the secondary volume
Can you incrementally reestablish the mirror from the newly restored source OR do you have to redo a baseline ???
2009-10-23 06:30 AM
My understanding is the QSM is based on a normal snapshot and once this relationship is lost you are into a new baseline. This is because NDMP and QSM are about the files in the volume. Snapmirror is all about the inodes which these higher level protocals know nothing about.
Hope it helps
2009-10-23 09:20 AM
Thank you Brendon
In fact, it is clear that a baseline is necessary if no common snapshot exist between source and destination :
After an NDMP restore -> no common snapshot -> baseline
But after a vol copy/VSM of the secondary backup volume, one should have a common snapshot (VSM or vol copy transfers active data AND all existing snapshots) and hence be able to resync between the two volumes, no ?
2009-10-26 08:45 AM
If you have lost the source, replaced it with new storage, performed a QSM baseline from the destination, then at that stage you will be able to "switch" tidily in order to go back to the new storage becoming the source once more & the destination becoming the destination again. That "switch" will not involve a baseline in any way. Does that answer your question ?
Detail for this is in the "Archive & Compliance" documentation on the NOW site - for example, for ONTAP 7.3.2, see http://now.netapp.com/NOW/knowledge/docs/ontap/rel732/pdfs/ontap/archive.pdf
Hope this helps