---
name: "cxl-set-partition"
section: "1"
platform: "linux"
package: "ndctl"
version: "85-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/cxl-set-partition"
---

# cxl-set-partition(1)

set the partitioning between volatile and persistent capacity on a CXL memdev

## NAME

cxl-set-partition - set the partitioning between volatile and persistent capacity on a CXL memdev

## SYNOPSIS

```
cxl set-partition <mem0> [ [<mem1>..<memN>] [<options>]
```

## DESCRIPTION

CXL devices may support both volatile and persistent memory capacity. The amount of device capacity set aside for each type is typically established at the factory, but some devices also allow for dynamic re-partitioning.

Use this command to partition a device into volatile and persistent capacity. The change in partitioning becomes the “next” configuration, to become active on the next device reset.

Use "cxl list -m \<memdev\> -I" to examine the partitioning capabilities of a device. A partition\_alignment\_size value of zero means there is no available capacity and therefore the partitions cannot be changed.

Using this command to change the size of the persistent capacity shall result in the loss of data stored.

## OPTIONS

\<memory device(s)\>

A *memX* device name, or a memdev id number. Restrict the operation to the specified memdev(s). The keyword *all* can be specified to indicate the lack of any restriction.

- \-S, --serial

  Rather an a memdev id number, interpret the \<memdev\> argument(s) as a list of serial numbers.

\-b, --bus=

Restrict the operation to the specified bus.

\-t, --type=

Type of partition, *pmem* or *ram* (volatile), to modify. Default: *pmem*

\-s, --size=

Size of the \<type\> partition in bytes. Size must align to the devices alignment requirement. Use *cxl list -m \<memdev\> -I* to find *partition\_alignment\_size*, or, use the --align option. Default: All available capacity is assigned to \<type\>.

- \-a, --align

  Select this option to allow the automatic alignment of --size to meet device alignment requirements. When using this option, specify the minimum --size of the --type partition needed. When this option is omitted, the command fails if --size is not properly aligned. Use *cxl list -m \<memdev\> -I* to examine the partition\_alignment\_size.

- \-v

  Turn on verbose debug messages in the library (if libcxl was built with logging and debug enabled).

## COPYRIGHT

Copyright © 2016 - 2022, Intel Corporation. License GPLv2: GNU GPL version 2  \<http://gnu.org/licenses/gpl.html\>. This is free software: you are free to change and redistribute it.  There is NO WARRANTY, to the extent permitted by law.

## SEE ALSO

[cxl-list(1)](/cxl-list/1.md), CXL-2.0 8.2.9.5.2