On Tue, September 1, 2009 10:56 am, George Spelvin wrote: > The fact that the ZFS decelopers observed drives writing the data to the > wrong location emphasizes the importance of keeping the checksum with > the pointer. An embedded checksum, no matter how good, can't tell you if > the data is stale; you need a way to distinguish versions in the pointer. I would disagree with that. If the embedded checksum is a function of both the data and the address of the data (in whatever address space seems most appropriate) then it can still verify that the data found with the checksum is the data that was expected. And storing the checksum with the data (where it is practical) means index blocks can be more dense so on average fewer accesses to storage are needed. NeilBrown -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
