Info
On any HPE servers running Red Hat Enterprise Linux 8.8, 8.9, 9.2, or 9.3 and using the Intel Virtual RAID on CPU (VROC), the corresponding
mdadm
grow command will not function properly to enable or disable Partial Parity Log (PPL) for the RAID Write Hole (RWH) protection feature on an existing RAID 5 volume, as shown below.
When the
mdadm --grow --consistency-policy=ppl /dev/mdxxx
command is executed to enable PPL, the command returns an error message:
mdadm: Subarray x in /dev/mdxxx is active, cannot update ppl
, similar to the following:
However, if the
mdadm
command is successful in enabling PPL, it does not return any output, and the result can be verified by checking the details of the volume. For a successful enabling of PPL, the "Consistency Policy" should be set to "ppl", as shown below:
Scope
This issue has been observed on HPE servers running Red Hat Enterprise Linux 8.8, 8.9, 9.2, or 9.3 and using the Intel Virtual RAID on CPU (VROC).
Resolution
As a workaround, perform either of the following:
On an operating system RAID 5 volume:
Reboot the server.
During the server Power-On Self-Test (POST), press
F9
.
From the System Utilities screen, select
System Configuration > Intel(R) SATA/sSATA/tSATA Controller or Intel(R) Virtual RAID on CPU > The designated RAID 5 volume > RWH Policy
.
From the drop-down list, select
Distributed PPL or Disable
.
Select
Change RWH settings
.
On a data RAID 5 volume, to ensure that there is no I/O to the RAID volume, perform the following:
Get the designated volume's sub-array index in the RAID container. In this example, "md127" is the container name:
# mdadm --examine /dev/md127
Stop the designated RAID 5 volume. In this example, "md126" is the RAID volume name:
# mdadm --stop /dev/md126
Use the "ppl" or the "no-ppl" option to enable or disable PPL on the designated volume's sub-array in the RAID container. In this example, the sub-array ID is "0", and "md127" is the container name:
# mdadm --update-subarray=0 --update=no-ppl /dev/md127
Assemble and activate the RAID volume:
# mdadm -As
This issue is still under investigation. This document will be updated as more information becomes available.
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