On 05.05.20 11:34, Wols Lists wrote:

No. The journal or bitmap are stored as part of the array, not the
filesystem. sdb will have a load of "flags" set to say "these blocks
were written to while the array was degraded". So when sda is added back
in, these delayed writes will be copied from sdb to sda.

When sdb copies the changes it has in the blocks /var/log sits on, will 
this result in the array showing the changes made to /var/log when it 
was booted using sdb only or did I get this wrong?