According to this web site, there is possibility we have race condition with
mdraid creation vs udev:
http://dev.bizo.com/2012/07/mdadm-device-or-resource-busy.html
And looks like it can happen on our AMI, too (see #2784).
To initialize RAID safely, we should wait udev events are finished before and
after mdadm executed.
Fixes #2784
Signed-off-by: Takuya ASADA <syuu@scylladb.com>
Message-Id: <1505898196-28389-1-git-send-email-syuu@scylladb.com>
(cherry picked from commit 4a8ed4cc6f)