Applies To

• Linux
• ndctl utility
• Systems with Persistent Memory

Issue

When disabling an persistent memory device (nmem), a notice is displayed indicating it is active, eg:

# ndctl disable-dimm nmem0
nmem0 is active, skipping...
disabled 0 nmem

Cause

The message indicates there’s at least one active/enabled Region and/or Namespace using the NVDIMM.

Solution

All active/enabled Regions and Namespaces must be destroyed an/or disabled prior to disabling the dimm.

1. List the current configuration (Namespaces, Regions, DIMMs):

# ndctl list -NRD

2. Verify no fsdax or devdax namespaces are mounted or in-use by running applications:

// Check for mounted file systems using the pmem devices
# df -h

// Check for any running processes that are currently accessing the namespaces
# fuser /dev/pmem0

3. Destroy or disable the namespace(s)

# ndctl destroy-namespace namespace0.0

4. Disable the regions used by the persistent memory decvice(s) that needs to be disabled:

# ndctl disable-region region0

5. Disable the persistent memory device (nmem)

# ndctl disable-dimm nmem0