Dear all,
I have been studying the basics of ONTAP and WAFL recently. Discussions on the Interent are very old and even official TR-3002 was moved away. I read several materials saying that
1. NVRAM is used to store JOURNAL but not DATA so it can be small but just enough
2. Data are wriiten to disk at each Consistent Point (CP), and between CPs data only go to DRAM with journal going to NVRAM
3. In case of power outage, journals are kept in NVRAM waiting to be replayed as the power come back
I wonder what WAFL is to do if power outage result in disappearance of data in DRAM; with only the journals, can WAFL simply finish what was not done yet?
Any reply would be appreciated. Thanks in advance.