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Version: 3.1

Add a dedicated journal device to a node in AKS

A journal device is a dedicated storage component used to improve the performance and reliability of write operations. It logs write operations before they are finalized in the main storage volumes. This page outlines how to configure a Portworx StorageCluster to add a journal device to a new or existing node.

Prerequisites

Before proceeding, ensure that:

  • The chosen journal device matches or surpasses the performance of the data pool devices.
  • Your setup does not use PX-StoreV2 backend.
  • The selected device or a partition on the selected device is not being used by any other service or applications.

Check your current journal device configuration

Before you begin, you may already have a journal device configured for your cluster. If you're unsure, you can check the current journal device configuration by running the pxctl status command and finding the Journal Device section:

pxctl status
...
Journal Device:
1 /dev/sdb1 STORAGE_MEDIUM_SSD 3.0 GiB
...

Add a journal device to a new node automatically

You can add a journal device to a new node automatically by editing your Portworx StorageCluster. Using this method, Portworx creates a partition from the existing storage pool drives:

storage:
useAll: true
journalDevice: auto
caution

You cannot use this method to add a journal device existing nodes.

Add journal device manually

You can use this method to add a journal device to a new or existing node manually. Done in this way, Portworx creates a journal device out of a drive, cloud drive, or partition you provide it.

Add journal device to a new node

Follow the steps in this section to edit your Portworx StorageCluster to add the size and type of the journal device you want to add for your environment.

  1. Run the command to edit your Portworx StorageCluster:

kubectl edit stc <px-cluster-ID> -namespace <px-namespace>

  1. Add the journalDeviceSpec parameter and specify the type and size of the device:

    spec:
    cloudStorage:
    deviceSpecs:
    - type=pd-standard,size=150
    journalDeviceSpec: type=<device-type>,size=<device-size>
  2. After you add a storage node, run the following command on a node to verify that a journal device is added:

    Status: PX is operational
    Telemetry: Disabled or Unhealthy
    Metering: Disabled or Unhealthy
    License: Trial (expires in 31 days)
    Node ID: xxxxxxxx-xxxx-xxxx-xxxx-6ccfb5c6b80a
    IP: 10.13.158.150
    Local Storage Pool: 1 pool
    POOL IO_PRIORITY RAID_LEVEL USABLE USED STATUS ZONE REGION
    0 HIGH raid0 384 GiB 12 GiB Online default default
    Local Storage Devices: 3 devices
    Device Path Media Type Size Last-Scan
    0:1 /dev/sdf STORAGE_MEDIUM_SSD 128 GiB 31 Jan 24 02:26 UTC
    0:2 /dev/sdd STORAGE_MEDIUM_SSD 128 GiB 31 Jan 24 02:26 UTC
    0:3 /dev/sde STORAGE_MEDIUM_SSD 128 GiB 31 Jan 24 02:26 UTC
    total - 384 GiB
    Cache Devices:
    * No cache devices
    Journal Device:
    1 /dev/sdb1 STORAGE_MEDIUM_SSD 3.0 GiB
    Metadata Device:
    1 /dev/sdc STORAGE_MEDIUM_SSD 64 GiB
    Cluster Summary
    Cluster ID: PX-xxx-0377
    Cluster UUID: 847373dd-xxxx
    Scheduler: none
    Total Nodes: 3 node(s) with storage (3 online)
    IP ID SchedulerNodeName Auth StorageNode Used Capacity Status StorageStatus Version Kernel OS
    10.xx.xxx xxxxxxxx-xxxx-xxxx-xxxx-4c988d5af111 N/A Disabled Yes 12 GiB 384 GiB Online Up 3.1.0.0-0a8098d 3.10.0-1160.80.1.el7.x86_64 CentOS Linux 7 (Core)
    10.xx.xxx xxxxxxxx-xxxx-xxxx-xxxx-b06882d44629 N/A Disabled Yes 12 GiB 384 GiB Online Up 3.1.0.0-0a8098d 3.10.0-1160.80.1.el7.x86_64 CentOS Linux 7 (Core)
    10.xx.xxx xxxxxxxx-xxxx-xxxx-xxxx-6ccfb5c6b80a N/A Disabled Yes 12 GiB 384 GiB Online Up (This node) 3.1.0.0-0a8098d 3.10.0-1160.80.1.el7.x86_64 CentOS Linux 7 (Core)

    You will see the journal device details in the status.

Add a journal device to an existing node

important

This workflow is not supported in a disaggregated cloud deployment. Contact the support team if your setup is disaggregated in a cloud environment.

To add a journal device to an existing node, follow the steps in this section:

  1. Switch the node to pool maintenance mode:

    pxctl service pool maintenance --enter
    This is a disruptive operation, PX will restart in maintenance mode.
    Are you sure you want to proceed ? (Y/N): Y

    Respond with Y when prompted.

  2. Confirm that the node is in pool maintenance mode:

    pxctl status
    Status: PX storage in pool maintenance
    Telemetry: Disabled or Unhealthy
    Metering: Disabled or Unhealthy
    License: PX-Enterprise (floating) (lease renewal in 6h, 4m)
    Node ID: xxxxxxxx-xxxx-xxxx-xxxx-f739ed673990
    IP: 10.xx.xxx.xxx
    Local Storage Pool: 1 pool
    POOL IO_PRIORITY RAID_LEVEL USABLE USED STATUS ZONE REGION
    0 HIGH raid0 2.0 TiB 1.0 TiB In Maintenance default default
    Local Storage Devices: 2 devices
    Device Path Media Type Size Last-Scan
    0:1 /dev/sdc STORAGE_MEDIUM_SSD 1021 GiB 15 Dec 23 15:02 UTC
    0:2 /dev/sdd STORAGE_MEDIUM_SSD 1.0 TiB 15 Dec 23 15:02 UTC
    total - 2.0 TiB
    Cluster Summary
    Cluster ID: PX-xxx
    Cluster UUID: xxxxxxxx-xxxx-xxxx-xxxx-2b9a5f67ba0e
    Scheduler: none
    Total Nodes: 9 node(s) with storage (8 online)
    IP ID SchedulerNodeName Auth StorageNode Used Capacity Status StorageStatus Version Kernel OS
    10.xx.xxx.xxx xxxxxxxx-xxxx-xxxx-xxxx-e4e9916fcde5 N/A Disabled Yes 879 GiB 2.0 TiB Online Up 3.1.0.0-4375431 4.20.13-1.el7.elrepo.x86_64 CentOS Linux 7 (Core)
    10.xx.xxx.xxx xxxxxxxx-xxxx-xxxx-xxxx-746abe26a72b N/A Disabled Yes 531 GiB 2.0 TiB Online Up 3.1.0.0-4375431 4.20.13-1.el7.elrepo.x86_64 CentOS Linux 7 (Core)
    10.xx.xxx.xxx xxxxxxxx-xxxx-xxxx-xxxx-f739ed673990 N/A Disabled Yes 20 GiB 350 GiB In Pool Maintenance Down (This node) 3.1.0.0-4375431 4.20.13-1.el7.elrepo.x86_64 CentOS Linux 7 (Core)
    10.xx.xxx.xxx xxxxxxxx-xxxx-xxxx-xxxx-312cb721e64f N/A Disabled Yes 1.0 TiB 2.0 TiB Online Up 3.1.0.0-4375431 4.20.13-1.el7.elrepo.x86_64 CentOS Linux 7 (Core)
    ...

    You should see a status output indicating that the node is in pool maintenance mode.

  3. Add the journal device. It is recommended to use an SSD/NVME for this purpose:

    pxctl service drive add --drive /dev/nvme01 --journal
    Successfully added journal device /dev/nvme010p1
  4. Exit the pool maintenance mode:

    pxctl service pool maintenance --exit
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