<div dir="ltr">according to <a href="http://linas.org/linux/raid.html">http://linas.org/linux/raid.html</a>:<br>(as of kernel 2.6.26 in July 2008):<p>
</p><ul><li>For a RAID-1 config with two disks, if the data mis-compare
was due to one block being unreadable, then the copy will be
made from the remaining, readable block, which should hold
good data. If both blocks were readable (<i>i.e.</i> were
read from the disk, without the disk indicating any sort of
error condition), but there was a mis-compare, then the data
from the highest-numbered disk is copied to the other disk.
This results in a 50-50 chance that good data was over-written
by bad. Furthermore, this is done silently: no syslog
messages indicate either a mis-compare, or that a repair
action was taken!</li></ul></div>