But this assume the blkxxxxx.dat file isn't corrupted, right?
Correct, if it detects a corrupted file on disk, it'll ignore the corrupted version and redownload the necessary blocks and verify them again. 
Topic: Re Index Function wallet is not syncing (Read 116 times)
is that mean all data storage on my local device is already lost?
If you are asking if the blocks you downloaded are lost, they aren't. Bitcoin Core doesn't delete in-good-shape blocks during a reindex, or after a sudden shutdown for that matter.
But if you mean if the data on your disk is lost, the answer is also no unless the disk is the one that failed. Other parts failing doesn't wipe the disk or make it unreadable. If you still aren't confident then get some software that runs SMART tests on your disks and check the results if they are OK. I don't know which operating system you're using so I can't make specific recommendations though.
Bitcoin Core should be asking you to do -reindex instead of -rescan. -rescan only makes the client run through the blockchain for any transactions associated with the address in the wallet. Running it with reindex simply means that Bitcoin Core attempts to rebuild the block database and the chainstate using the blocks that are already on the disk. It doesn't re-download existing blocks but it will verify and restructure the files instead.
I guess I got some hardware failure and bitcoin daemon suggest the following
local blockchain database broken / corrupt? This can occur when copying blockchain from one computer to another, when you update wallet incorrectly, or when you shutdown your wallet non-gracefully.
is that mean all data storage on my local device is already lost?
local blockchain database broken / corrupt? This can occur when copying blockchain from one computer to another, when you update wallet incorrectly, or when you shutdown your wallet non-gracefully.
Code:
-rescan
is that mean all data storage on my local device is already lost?
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