Persistent memory support

StorPool supports journaling for hard disks on persistent-memory devices; for example, Intel Optane Persistent Memory 200 Series.


Persistent memory devices are fast enough and provide a reasonable guarantee for power-loss protection to be usable for journaling (persisting) and completing operations quickly, without waiting for a confirmation from the underlying hard disk. When you cannot use such devices, you have to choose between either the power-loss protected cache of a RAID controller, or a NVMe device.


You need to create partitions on a pmem namespace with ndctl as follows:

  1. Create a namespace with ndctl create-namespace.

    The size should be as large as to fit the number of needed 100MiB journals.

  2. In the namespace, create partitions, 100MiB for each journal, aligned on 1MiB boundaries.

  3. For each hard disk being initialized, pass on the /dev/pmem... device as a journal.


This feature is available starting with the 19.3 revision 19.01.2539.30ba167e1 release.