On 4/3/19 5:15 AM, Konstantin Msk via CentOS wrote: > Hello! > > On my server PC i have Centos 7 installed. > CentOS Linux release 7.6.1810. > There are four arrays RAID1 (software RAID) > md124 - /boot/efi > md125 - /boot > md126 - /bd > md127 - / > > I have configured booting from both drives, everything works fine if both drives are connected. > But if I disable any drive from which RAID1 is built the system crashes, there is a partial boot and as a result the Entering emergency mode. > By all rules RAID1 in case of similar failure of one of disks the system has to recognize this moment at loading, analyze that from the array only one disk is available and forcibly assemble inactive RAID array in case it is degraded in the mode when the second disk is missing may be... [please use a subject appropriate to the message.] I believe you are hitting this bug: https://bugzilla.redhat.com/show_bug.cgi?id=1451660 That is, if a drive is unplugged while the system is not running, mdadm will not reassemble the array on boot. If a drive fails while the system is running, mdadm should fail it out of the array and the system will boot properly. Hoping for a fix in the next minor release.