Thu 07 Jan 2021

dd, bs= and why you should use conv=fsync

Long story short: If one uses dd with a bigger block size (>= 4096), be sure to use either the oflag=direct or conv=fsync option to have proper error reporting while writing data to a device. I would prefer conv=fsync, dd will then fsync() the file handle once and report the error, without having the performance impact which oflag=direct has.

Source: dd, bs= and why you should use conv=fsync, an article by Michael Ablassmeier.