How to fix a catapult node that crash without resyncing

# If your catapult node crash with some missing blocks, due to the way catapult broker works, the catapult index.dat is updated and buffered in memory before the block is saved to the disk.
# On the event of a node crashing, this will cause the block to be unable to recover

To start, 

vim index.dat

:set binary !
:%!xxd

Edit the text file to the last block height on the disk

Before saving the file
:%!xxd -r


Delete blocks on disk that have size 0

Start server

Use https://www.rapidtables.com/convert/number/decimal-to-hex.html to convert the number

Note that the order is reversed, that means

1234 5678 9ABC

is

BC9A 7856 3412 in Hex number (unsigned) = 170133695238708

1 folder has 65535 blocks