PowerFlex: Disk path changed to /dev/mdXXX after reboot

Failed devices in the UI and CLI:
 

lsblk output is similar to the output below:
 

The server was previously using software RAID:
 

NOTE: Multiple device failures may lead to DU.

The disks were previously used by software RAID. 

Reference: https://en.wikipedia.org/wiki/Mdadm

NOTE: The following assumes that the software raid configuration exists on the devices before they were added as PowerFlex SDS devices. If the disks were configured in any software raid after they have been added as PowerFlex devices, some user data may have been corrupted.

Workaround

• Stop the raid device with the following command:

  mdadm /dev/mdX --stop

  Or

  mdadm /dev/mdX --remove /dev/sdX
  

• If there is no /dev/mdXXX device, but there is a /dev/ddf* device, then the software raid device may have been activated by a different software, such as dmraid-activation. Disable the service with the following command, and restart the server to see that the /dev/ddf* device files are not created:

  systemctl disable dmraid-activation
  

• If the above do not work, add the following into /opt/emc/scaleio/sds/cfg/conf.txt, restart the SDS process (e.g. pkill sds) and then clear device error:

  tgt_dev__enable_multipath=1
  

Permanent Solution

After applying one of the above workarounds to clear device error, do the following to permanently remove software raid meta data that is stored on the disk:

• Remove the device from PowerFlex, wait for rebalance to complete and the device is removed.

• Run this command to delete metadata on disk.

  mdadm --zero-superblock /dev/sdX
  

• Add the disk as SDS device back into PowerFlex.